docs: migration headers keep the before and after, without ids, quotes or one library's numbers (#6277)

Applies rule 32's migration exception: each header still says what the
schema was, what changes and what it prevents, but task, milestone,
decision and rule ids are replaced by the practice they stood for, the
operator quotes by the decision, single-install counts are dropped, and
pointers to a deleted package and an external design doc are gone.
golang-migrate keeps no checksum, so editing applied migrations'
comments is safe.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/db/migrations/0077_track_source_verdict.up.sql

@@ -1,13 +1,12 @@
 -- 0077_track_source_verdict.up.sql — video rips are held back from mixes and
--- radio until the operator says otherwise (Scribe milestone #498, #5439;
--- operator decision D-d).
+-- radio until an admin says otherwise.
 --
--- A file whose name carries a video-rip marker ("(Official Video)", "[HD]",
--- #5410) holds the audio of an upload, which can carry intros, skits or a
+-- A file whose name carries a video-rip marker ("(Official Video)", "[HD]")
+-- holds the audio of an upload, which can carry intros, skits or a
 -- different take. The duplicate resolver sets 'suspect' on such a present
 -- track each pass, and clears it when the name no longer matches. 'suspect'
 -- keeps the track out of radio and the system mixes; it still plays when
--- chosen. 'fine' is the operator's "this one is fine" and is never
+-- chosen. 'fine' is an admin's "this one is fine" and is never
 -- overwritten by the resolver.
 ALTER TABLE tracks ADD COLUMN source_verdict text
     CONSTRAINT tracks_source_verdict_check CHECK (source_verdict IN ('suspect', 'fine'));