feat: a tick keeps looking back 30 days, so an EDITED post is reached (4386)

Operator, 2026-09-23, on a Floppystack post: "this post has been updated as
he implements hot fixes — any chance we have a way to scan for or see updated
posts so we can update ours to match and pull the new attachments and
pictures etc."

The download half already worked: extract_media reads the media list off the
LIVE feed response every walk, so a newly attached hotfix build is a ledger
key we have never seen. Only REACHING the post was missing — a tick stopped
after 20 contiguous already-have-it items, and a post edited three days after
publication sits well below twenty. Not a bug in the early-out; a count
cannot express "recent".

The early-out now needs BOTH conditions: the run of seen items AND a post
published before the horizon. Strictly a widening — window 0 is exactly the
old behaviour, and no window can make a tick stop EARLIER than it used to, so
a source paused for months still walks its whole unseen backlog. The horizon
is a floor on how far to look, never a ceiling.

Inside the window the post-record gate is bypassed too (write_post_record
revisit=True): the body is re-read from the feed response already in hand, so
a revisit costs zero requests, and a body that comes back empty writes
NOTHING rather than blanking one a detail-fetch had filled. Revisits are kept
out of the #862 body-drift canary's sample for the same reason — an empty
revisit is healthy, and counting it would walk the alarm toward firing on
good ticks.

The run summary names what changed ("3 post(s) updated (5 new file(s))") with
a line per post; the ask was to SEE updated posts, not only to end up with
their bytes.

download_revisit_days is a settings row, not a constant (rule 25) — how long
a creator keeps editing is a property of the creator. Default 30, 0 turns it
off. Migration 0108.

Also corrects two stale docstrings: both clients described post_meta as
feeding an Ingester.preview that no longer calls it. It had no consumer at
all until this change.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LVjrnpQjRgHdvq95rASoiR

alembic/versions/0108_download_revisit_days.py

@@ -0,0 +1,54 @@
+"""download_revisit_days — how far back a tick keeps looking for EDITED posts.
+
+Operator, 2026-09-23, pointing at a Floppystack post: *"this post has been
+updated as he implements hot fixes — any chance we have a way to scan for or
+see updated posts so we can update ours to match and pull the new attachments
+and pictures etc."*
+
+A tick stopped after 20 contiguous already-have-it items. That is the right
+instinct and the wrong unit: a post edited three days after publication sits
+well below twenty seen items, so the walk turned around before reaching it. The
+walk now needs BOTH a run of seen items and a post older than this many days
+before it stops.
+
+A settings row rather than a constant (rule 25) because the right window is a
+property of the CREATOR, not of FabledCurator — one artist appends hotfix
+builds for a fortnight, another never touches a post again. 0 turns the revisit
+off entirely and restores the pure count early-out.
+
+30 days is the operator's own number, 2026-09-23.
+
+Revision ID: 0108
+Revises: 0107
+Create Date: 2026-09-23
+
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0108"
+down_revision: Union[str, None] = "0107"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # server_default so the existing single settings row gets the window without
+    # a data migration — and so an install that predates this column reads 30
+    # rather than 0. 0 is a real, meaningful value here (revisit off), so the
+    # column must never be allowed to arrive at it by omission.
+    op.add_column(
+        "import_settings",
+        sa.Column(
+            "download_revisit_days",
+            sa.Integer(),
+            nullable=False,
+            server_default="30",
+        ),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("import_settings", "download_revisit_days")