feat(supersession): the relation, and the dead column that stood where it should

Step 1 of #278. Structure only — nothing reads or writes the new table yet.

Old records outrank newer ones on the same subject because a similarity score
cannot tell time. A note that accurately described how something worked in June
is still accurate ABOUT June; it is just no longer the answer. Nothing recorded
that, so nothing could act on it.

`note_supersessions(superseder_id, superseded_id)`. The claim points FORWARD —
the newer record names what it overtakes — because the older one cannot know it
has been overtaken; asking it to record its own obsolescence is asking it to
predict the future.

A table rather than a column because the relation is genuinely many-to-many and
partial, and both directions are hot: superseded_id answers "has this been
overtaken?" at ranking time, superseder_id answers "what does this replace?" in
a record view. An array column serves one and not the other.

CASCADE is safe because trashing is not a delete — trash_svc stamps deleted_at,
so a trashed note keeps its claims and restore brings them back. It fires only
on purge_trash, where a claim about the row would be unactionable anyway. A
CHECK rejects self-supersession, which under flat demotion would let a record
demote itself.

## consolidated_at, and what it actually was

Dropped. Written by nothing while serialised into every note and task payload
as null — and worse, it implied a capability.

The survey (#2483) read it as note consolidation modelled and abandoned. That
was wrong, and the frontend is what says so: `TaskViewerView` rendered
"✦ Auto-summarized from work logs" gated on this column. It is a survivor of
the pre-pivot auto-summary subsystem (migration 0030), whose own column #599
removed. Not an unbuilt feature — an outlived one.

So four more remnants went with it: the banner, its CSS, a `consolidatedAt` ref
in TaskEditorView assigned and never read, and `.auto-summary-banner-editor`
styling with zero template usage. That last one is presence-without-reference
in the same family as the column itself.

Dropped rather than repurposed for supersession, and the distinction is the
point: consolidation folds records into one survivor and destroys the
originals. Supersession is the opposite — both survive, the older ranks behind.
Smuggling one in under a column named for the other would bury that in schema.

## The hard delete_note

Removed, with a comment where it stood. Zero callers, and the danger was never
that it ran — it is that it was findable by name. Someone wanting to delete a
note greps `delete_note`, finds a function in the notes service with exactly
the right signature, and permanently destroys a record every path downstream
expects to be recoverable. The MCP tool of the same name already went through
trash_svc; only the service function was the trap.

Refs #278, #2483

alembic/versions/0076_note_supersessions.py

@@ -0,0 +1,115 @@
+"""note_supersessions; drop the never-written notes.consolidated_at
+
+Revision ID: 0076
+Revises: 0075
+Create Date: 2026-08-07
+
+Step 1 of milestone #278. Structure only — nothing reads or writes the new
+table yet, and nothing behaves differently after this runs.
+
+## What the table is for
+
+Old records outrank newer ones on the same subject, because a similarity score
+cannot tell time. A note that accurately described how something worked in June
+is still accurate ABOUT June; it is just no longer the answer. Nothing recorded
+that, so nothing could act on it.
+
+The claim points FORWARD — the newer record names what it overtakes — because
+the older one cannot know it has been overtaken. Many-to-many and partial: a
+note may supersede parts of several others and be overtaken piecemeal by
+several later ones, which is why this is a table rather than a column. Both
+directions are queried: `superseded_id` answers "has this been overtaken?" at
+ranking time, `superseder_id` answers "what does this replace?" in a record
+view. An array column could serve one and not the other.
+
+CASCADE on both sides is safe because trashing is not a delete: `trash_svc`
+stamps `deleted_at`, so a trashed note keeps its claims and `restore` brings
+them back. The cascade fires only on `purge_trash`, where the row genuinely
+goes — and a claim about a row that no longer exists is not actionable.
+
+## What is being dropped, and why now
+
+`notes.consolidated_at` was written by NOTHING — no service, no route, no tool
+— while being serialised into every note and task payload as `null`. It cost a
+column, a line in every response, and worse: it IMPLIED a capability. A reader
+reasonably concludes notes can be consolidated and this records when.
+
+That reading was reasonable precisely because merge/unmerge exists for snippets
+and not for notes, so the column looked like the notes-side half of that
+feature, modelled and abandoned.
+
+It is dropped rather than repurposed for supersession, and the distinction is
+the point (#2483): consolidation folds several records into one survivor and
+destroys the originals. Merging two snippets is lossless — one helper, several
+call sites. Folding two dev-logs means writing a summary and losing what each
+actually said. Supersession is the opposite act: both records survive, and the
+older one is merely ranked behind. Smuggling one in under a column named for
+the other would have buried that difference in schema.
+
+## Downgrade
+
+Re-adds `consolidated_at` nullable, which is how it lived — so downgrade
+restores the shape, not the (nonexistent) data. Drops the table; any recorded
+supersession claims are lost, which costs ranking its input and nothing else,
+since no note's own content depends on them.
+"""
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0076"
+down_revision = "0075"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "note_supersessions",
+        sa.Column("id", sa.Integer, primary_key=True),
+        sa.Column(
+            "superseder_id",
+            sa.Integer,
+            sa.ForeignKey("notes.id", ondelete="CASCADE"),
+            nullable=False,
+        ),
+        sa.Column(
+            "superseded_id",
+            sa.Integer,
+            sa.ForeignKey("notes.id", ondelete="CASCADE"),
+            nullable=False,
+        ),
+        sa.Column(
+            "created_at",
+            sa.DateTime(timezone=True),
+            server_default=sa.text("now()"),
+            nullable=False,
+        ),
+        sa.UniqueConstraint(
+            "superseder_id", "superseded_id", name="uq_note_supersessions_pair"
+        ),
+        # Declaring that a note supersedes ITSELF is meaningless, and under flat
+        # demotion it would demote a record on its own authority. Refused in the
+        # service too, with a message — this is the backstop that holds when
+        # something writes rows directly.
+        sa.CheckConstraint(
+            "superseder_id <> superseded_id", name="ck_note_supersessions_not_self"
+        ),
+    )
+    op.create_index(
+        "ix_note_supersessions_superseder", "note_supersessions", ["superseder_id"]
+    )
+    op.create_index(
+        "ix_note_supersessions_superseded", "note_supersessions", ["superseded_id"]
+    )
+
+    op.drop_column("notes", "consolidated_at")
+
+
+def downgrade() -> None:
+    op.add_column(
+        "notes",
+        sa.Column("consolidated_at", sa.DateTime(timezone=True), nullable=True),
+    )
+    op.drop_index("ix_note_supersessions_superseded", table_name="note_supersessions")
+    op.drop_index("ix_note_supersessions_superseder", table_name="note_supersessions")
+    op.drop_table("note_supersessions")

frontend/src/types/note.ts

@@ -10,7 +10,6 @@ export interface Note {
   title: string;
   body: string;
   description: string | null;
-  consolidated_at: string | null;
   tags: string[];
   parent_id: number | null;
   parent_title?: string | null;

frontend/src/views/TaskEditorView.vue

@@ -41,7 +41,6 @@ const toast = useToastStore();
 const title = ref("");
 const body = ref("");
 const description = ref("");
-const consolidatedAt = ref<string | null>(null);
 const tags = ref<string[]>([]);
 const status = ref<TaskStatus>("todo");
 const priority = ref<TaskPriority>("none");
@@ -303,7 +302,6 @@ onMounted(async () => {
       title.value = store.currentTask.title;
       body.value = store.currentTask.body;
       description.value = store.currentTask.description ?? "";
-      consolidatedAt.value = store.currentTask.consolidated_at ?? null;
       tags.value = [...(store.currentTask.tags || [])];
       status.value = store.currentTask.status as TaskStatus;
       priority.value = store.currentTask.priority as TaskPriority;
@@ -1063,22 +1061,4 @@ useEditorGuards(dirty, save);
   border-color: var(--color-primary);
 }
 
-/* ── Auto-summary banner + re-consolidate button ─────────────────────────── */
-.auto-summary-banner-editor {
-  display: flex;
-  align-items: center;
-  gap: 0.6rem;
-  padding: 0.45rem 0.7rem;
-  margin-bottom: 0.5rem;
-  font-size: 0.82rem;
-  font-style: italic;
-  color: var(--color-text-muted);
-  background: rgba(99, 102, 241, 0.06);
-  border-left: 2px solid var(--color-primary);
-  border-radius: var(--radius-sm);
-}
-.auto-summary-banner-editor .auto-summary-icon {
-  color: var(--color-primary);
-  font-style: normal;
-}
 </style>

frontend/src/views/TaskViewerView.vue

@@ -365,13 +365,6 @@ const subTaskProgress = computed(() => {
           <p class="goal-text">{{ store.currentTask.description }}</p>
         </div>
 
-        <div
-          v-if="store.currentTask.consolidated_at"
-          class="auto-summary-banner"
-        >
-          <span class="auto-summary-icon" aria-hidden="true">✦</span>
-          Auto-summarized from work logs.
-        </div>
 
         <div
           class="body prose"
@@ -771,17 +764,4 @@ const subTaskProgress = computed(() => {
   color: var(--color-text);
   white-space: pre-wrap;
 }
-.auto-summary-banner {
-  display: flex;
-  align-items: center;
-  gap: 0.5rem;
-  font-size: 0.78rem;
-  font-style: italic;
-  color: var(--color-text-muted);
-  margin: 0 0 0.75rem;
-}
-.auto-summary-icon {
-  color: var(--color-primary);
-  font-size: 0.85rem;
-}
 </style>

src/scribe/models/__init__.py

@@ -33,6 +33,7 @@ from scribe.models.milestone import Milestone  # noqa: E402, F401
 from scribe.models.task_log import TaskLog  # noqa: E402, F401
 from scribe.models.note_draft import NoteDraft  # noqa: E402, F401
 from scribe.models.note_version import NoteVersion  # noqa: E402, F401
+from scribe.models.note_supersession import NoteSupersession  # noqa: E402, F401
 from scribe.models.group import Group, GroupMembership  # noqa: E402, F401
 from scribe.models.share import NoteShare, ProjectShare  # noqa: E402, F401
 from scribe.models.notification import Notification  # noqa: E402, F401

src/scribe/models/note.py

@@ -33,9 +33,6 @@ class Note(Base, TimestampMixin, SoftDeleteMixin):
     title: Mapped[str] = mapped_column(Text, default="")
     body: Mapped[str] = mapped_column(Text, default="")
     description: Mapped[str | None] = mapped_column(Text, nullable=True)
-    consolidated_at: Mapped[datetime | None] = mapped_column(
-        DateTime(timezone=True), nullable=True
-    )
     tags: Mapped[list[str]] = mapped_column(ARRAY(Text), default=list)
     parent_id: Mapped[int | None] = mapped_column(
         Integer, ForeignKey("notes.id", ondelete="SET NULL"), nullable=True
@@ -101,9 +98,6 @@ class Note(Base, TimestampMixin, SoftDeleteMixin):
             "title": self.title,
             "body": self.body,
             "description": self.description,
-            "consolidated_at": (
-                self.consolidated_at.isoformat() if self.consolidated_at else None
-            ),
             "tags": self.tags or [],
             "parent_id": self.parent_id,
             "arose_from_id": self.arose_from_id,

src/scribe/models/note_supersession.py

@@ -0,0 +1,70 @@
+from sqlalchemy import ForeignKey, Index, Integer, UniqueConstraint
+from sqlalchemy.orm import Mapped, mapped_column
+
+from scribe.models import Base
+from scribe.models.base import CreatedAtMixin
+
+
+class NoteSupersession(Base, CreatedAtMixin):
+    """A newer record's claim that it has overtaken an older one.
+
+    WHY THE RELATION POINTS FORWARD
+
+    The note being WRITTEN declares what it supersedes. The old record cannot
+    know it has been overtaken — asking it to record its own obsolescence is
+    asking it to predict the future. So the claim is made by the party that has
+    the knowledge, and the demotion is derived from the far end.
+
+    WHY A TABLE RATHER THAN A COLUMN
+
+    It is genuinely many-to-many and partial: one note may supersede parts of
+    several others, and a note may be overtaken piecemeal by several later ones.
+    Both directions are queried and neither is rare —
+    `superseded_id` answers the ranking question ("has this been overtaken?"),
+    `superseder_id` answers the record view ("what does this replace?"). An
+    array column on `notes` could be indexed for one and not the other.
+
+    WHAT IT MEANS, AND WHAT IT DOES NOT
+
+    A claim, never a proof. Supersession DEMOTES a record in ranked retrieval;
+    it does not assert the older record was wrong, and it never hides it. A note
+    that accurately described how something worked in June is still accurate
+    about June — it is just no longer the answer to "how does this work".
+
+    CASCADE IS SAFE HERE BECAUSE TRASHING IS NOT A DELETE
+
+    `trash_svc` stamps `deleted_at` (an UPDATE), so a trashed note keeps its
+    claims and `restore` brings them back intact. The cascade fires only on
+    `purge_trash`, where the row genuinely goes — and a supersession claim about
+    a row that no longer exists is not a fact anyone can act on.
+    """
+
+    __tablename__ = "note_supersessions"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    # The newer record, making the claim.
+    superseder_id: Mapped[int] = mapped_column(
+        Integer, ForeignKey("notes.id", ondelete="CASCADE")
+    )
+    # The older record, demoted by it.
+    superseded_id: Mapped[int] = mapped_column(
+        Integer, ForeignKey("notes.id", ondelete="CASCADE")
+    )
+
+    __table_args__ = (
+        UniqueConstraint(
+            "superseder_id", "superseded_id", name="uq_note_supersessions_pair"
+        ),
+        # Both directions indexed — see the class docstring for why neither is
+        # the rare one.
+        Index("ix_note_supersessions_superseder", "superseder_id"),
+        Index("ix_note_supersessions_superseded", "superseded_id"),
+    )
+
+    def to_dict(self) -> dict:
+        return {
+            "id": self.id,
+            "superseder_id": self.superseder_id,
+            "superseded_id": self.superseded_id,
+            "created_at": self.created_at.isoformat() if self.created_at else None,
+        }

src/scribe/services/notes.py

@@ -373,17 +373,16 @@ async def update_note(user_id: int, note_id: int, **fields: object) -> Note | No
     return note
 
 
-async def delete_note(user_id: int, note_id: int) -> bool:
-    async with async_session() as session:
-        result = await session.execute(
-            select(Note).where(Note.id == note_id, Note.user_id == user_id)
-        )
-        note = result.scalars().first()
-        if note is None:
-            return False
-        await session.delete(note)
-        await session.commit()
-        return True
+# A hard `delete_note(user_id, note_id)` lived here with ZERO callers, and was
+# removed with #278 step 1. It is recorded rather than silently dropped because
+# the danger was never that it ran — it is that it was findable by name. Someone
+# wanting to delete a note greps `delete_note`, finds a function in the notes
+# service with exactly the right signature, and permanently destroys a record
+# every path downstream expects to be recoverable.
+#
+# The delete path is `trash_svc.delete`, which soft-deletes an entity AND its
+# descendants under one batch_id so `restore(batch)` works. `purge_trash` owns
+# permanent deletion. Both are reachable; neither is spelled `delete_note`.
 
 
 async def get_all_tags(user_id: int, q: str | None = None) -> list[str]: