M1: notes model + migration 0002 + notes API (CRUD, trash/restore)

- Note model (owner_id, title, body, color-key, pinned, archived, deleted_at
  soft-delete, timestamps) + board index; NOTE_COLORS palette keys.
- Migration 0002 (notes table + ix_notes_owner_board).
- /api/notes blueprint (login_required): list (?filter=active|archived|trash,
  pinned-then-updated, read via visible_to_user ACL), create, get, patch
  (title/body/color/pinned/archived), trash, restore, permanent delete
  (trash-only). Mutations owner-scoped; empty note rejected (400).
- DB-free unit tests: is_empty_note, normalize_color, palette, serialize,
  auth-guard on list/create.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FRgehjoz7Yv8LkUfADxACm

alembic/versions/0002_notes.py

@@ -0,0 +1,38 @@
+"""notes
+
+Revision ID: 0002
+Revises: 0001
+Create Date: 2026-07-19
+
+The M1 capture core: the notes table the masonry board renders.
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import UUID
+
+revision = "0002"
+down_revision = "0001"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "notes",
+        sa.Column("id", UUID(as_uuid=True), primary_key=True),
+        sa.Column("owner_id", UUID(as_uuid=True), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False),
+        sa.Column("title", sa.Text(), nullable=True),
+        sa.Column("body", sa.Text(), nullable=False, server_default=""),
+        sa.Column("color", sa.Text(), nullable=False, server_default="default"),
+        sa.Column("pinned", sa.Boolean(), nullable=False, server_default=sa.false()),
+        sa.Column("archived", sa.Boolean(), nullable=False, server_default=sa.false()),
+        sa.Column("deleted_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False, server_default=sa.func.now()),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False, server_default=sa.func.now()),
+    )
+    op.create_index("ix_notes_owner_board", "notes", ["owner_id", "deleted_at", "archived", "pinned"])
+
+
+def downgrade() -> None:
+    op.drop_index("ix_notes_owner_board", table_name="notes")
+    op.drop_table("notes")