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

backend/app/api/settings.py

@@ -36,6 +36,7 @@ _EDITABLE_FIELDS = (
     "download_validate_files",
     "download_schedule_default_seconds",
     "download_event_retention_days",
+    "download_revisit_days",
     "download_failure_warning_threshold",
     "series_suggest_enabled",
     "series_suggest_threshold",
@@ -113,6 +114,12 @@ async def update_import_settings():
         v = body["download_schedule_default_seconds"]
         if not isinstance(v, int) or isinstance(v, bool) or v < 60 or v > 86400:
             return _bad_int("download_schedule_default_seconds", 60, 86400)
+    # 0 is a real value (revisit off), so the floor is 0, not 1 — and the
+    # ceiling is a year, past which a "tick" is a backfill wearing a hat.
+    if "download_revisit_days" in body:
+        v = body["download_revisit_days"]
+        if not isinstance(v, int) or isinstance(v, bool) or v < 0 or v > 365:
+            return _bad_int("download_revisit_days", 0, 365)
     if "download_event_retention_days" in body:
         v = body["download_event_retention_days"]
         if not isinstance(v, int) or isinstance(v, bool) or v < 1 or v > 3650: