docs: library comments say what the scanner and resolver do, not how they came to be (#6277)

Rewrites the internal/library comment blocks to rule 32. Task, milestone,
decision and rule ids are gone; the incidents behind them are restated as
the constraint they left (why a file is deleted before its row, why the
missing mark is a mark, why duplicates block on duration). Counts and
album names from one library are dropped from production comments; test
comments keep the names their fixtures use. The tagReadVersion log keeps
each version's before and after, without the measurements.

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

internal/library/fingerprint.go

@@ -18,7 +18,7 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
 )
 
-// Acoustic identity (M400).
+// Acoustic identity.
 //
 // Two values per track, because they answer different questions:
 //
@@ -26,7 +26,7 @@ import (
 //	                     same audio bytes, whatever the tags or container around
 //	                     them say. No threshold and no false positives — this is
 //	                     what catches two copies of one MP3 that differ only in
-//	                     their ID3 (#3885).
+//	                     their ID3.
 //
 //	chromaprint          fpcalc's raw fingerprint. Close means the same
 //	                     recording, even at another bitrate or in another codec
@@ -39,9 +39,9 @@ import (
 
 // fingerprintTimeout bounds one ffmpeg hash or fpcalc call. Longer than
 // probeTimeout because both read the audio rather than a header: the hash reads
-// every packet and fpcalc decodes up to its -length. 60s leaves room for a large
-// lossless file on a slow network mount; a call needing more is a stall, not a
-// big file.
+// every packet and fpcalc decodes up to its -length. 60s leaves room for a
+// large lossless file on a slow network mount; a call needing more is a stall,
+// not a big file.
 const fingerprintTimeout = 60 * time.Second
 
 // fingerprintWaitDelay bounds how long Output may keep waiting on the tool's
@@ -52,9 +52,10 @@ const fingerprintWaitDelay = 5 * time.Second
 // fingerprintVersion stamps how a track_fingerprints row was derived. Bump it
 // whenever the derivation changes — the hash arguments or fpcalc's flags — and
 // the backfill re-derives every row below it. Fingerprints taken by two methods
-// are not comparable, and nothing else would reveal that the library held a mix.
+// are not comparable, and nothing else would reveal that the library held a
+// mix.
 //
-// The length is deliberately not part of it: it is an operator setting (#3913),
+// The length is deliberately not part of it: it is an admin setting,
 // so each row records the length it was taken at and readers compare only rows
 // at the current one. See fingerprint_settings.go.
 const fingerprintVersion int16 = 1
@@ -63,7 +64,7 @@ const fingerprintVersion int16 = 1
 // failed exit because a stall is a fact about the mount, not about the file.
 var errFingerprintTimeout = errors.New("fingerprint tool timed out")
 
-// defaultChromaprintLengthSec is the shipped value of the length setting (#3913):
+// defaultChromaprintLengthSec is the shipped value of the length setting:
 // how many seconds of audio fpcalc fingerprints. 120 is fpcalc's own default.
 const defaultChromaprintLengthSec = 120
 
@@ -99,10 +100,10 @@ func streamHashArgs(path string) []string {
 // fpcalcArgs asks for the raw fingerprint as SIGNED integers.
 //
 // -raw because the matcher compares items bit by bit, which the compressed form
-// cannot do without being unpacked first. -signed because the column is Postgres
-// integer[], which is signed: fpcalc's default prints uint32, and half of those
-// values do not fit. Signed output is the same 32 bits with no reinterpretation
-// step left to get wrong.
+// cannot do without being unpacked first. -signed because the column is
+// Postgres integer[], which is signed: fpcalc's default prints uint32, and half
+// of those values do not fit. Signed output is the same 32 bits with no
+// reinterpretation step left to get wrong.
 func fpcalcArgs(path string, lengthSec int) []string {
 	return []string{
 		"-raw", "-signed",
@@ -112,7 +113,7 @@ func fpcalcArgs(path string, lengthSec int) []string {
 }
 
 // lookupFingerprintLengthSec is how much audio the AcoustID lookup print
-// covers (M401). Fixed at fpcalc's default rather than following the
+// covers. Fixed at fpcalc's default rather than following the
 // duplicate-detection length setting: AcoustID's database is built from
 // prints that taggers such as Picard take at the default, and a lookup print
 // of a different span matches it less well.
@@ -120,7 +121,7 @@ const lookupFingerprintLengthSec = 120
 
 // fpcalcLookupArgs asks for the COMPRESSED fingerprint, fpcalc's default
 // output and the string AcoustID's lookup takes. A second decode beside the
-// raw print, chosen over re-encoding the stored raw array in Go (M401 D1):
+// raw print, chosen over re-encoding the stored raw array in Go:
 // fpcalc is the reference encoder, while a subtle bug in a port would still
 // produce a well-formed string that AcoustID answers with "no match".
 func fpcalcLookupArgs(path string) []string {
@@ -147,8 +148,8 @@ type fingerprintResult struct {
 }
 
 // fingerprintOptions is what the settings decide for one attempt. Captured once
-// per file, so the length a chromaprint was taken at is the length stored with it
-// even if the setting changes mid-attempt.
+// per file, so the length a chromaprint was taken at is the length stored with
+// it even if the setting changes mid-attempt.
 type fingerprintOptions struct {
 	lengthSec int32
 	// chromaprint false takes the stream hash alone: a demux, no decode.
@@ -208,11 +209,11 @@ const (
 )
 
 // storeFingerprint records one attempt, for the scan (new or changed bytes) and
-// the backfill (#3908) alike, so there is one rule for what gets written. It
+// the backfill alike, so there is one rule for what gets written. It
 // never fails its caller: a missing fingerprint only keeps a track out of
 // duplicate detection, which is not worth dropping a scan or a pass over.
 //
-// lengthSec is the length fp's chromaprint was taken at, stored with it (#3913).
+// lengthSec is the length fp's chromaprint was taken at, stored with it.
 func storeFingerprint(
 	ctx context.Context, q *dbq.Queries, logger *slog.Logger,
 	trackID pgtype.UUID, path string, fp fingerprintResult, lengthSec int32,
@@ -284,8 +285,8 @@ func computeLookupFingerprint(ctx context.Context, path string) (lookupFingerpri
 
 // runFingerprintTool runs one tool under fingerprintTimeout.
 //
-// Any non-zero exit is an error, and that deliberately includes fpcalc's exit 3:
-// "reading failed, but here is a fingerprint of what I got". A partial
+// Any non-zero exit is an error, and that deliberately includes fpcalc's exit
+// 3: "reading failed, but here is a fingerprint of what I got". A partial
 // fingerprint of a damaged file is not that file's identity. Stored, it would
 // score against a healthy copy over whatever prefix survived, and could group
 // or fail to group either way. Absent is better than wrong.
@@ -336,11 +337,10 @@ func (e *toolExitError) Error() string {
 const fpcalcExitPartial = 3
 
 // fpcalcReadToEnd reports whether fpcalc's partial exit only means it decoded
-// the whole file (#6178). The image's fpcalc 1.5.1 reports the decoder's end of
-// file as "Error decoding audio frame (End of file)" and exits 3 whenever it
-// reaches the end before -length, so it failed every file shorter than the
-// span asked for: every track under two minutes, at any length setting. That
-// print covers the whole file, so it is the file's identity.
+// the whole file. The image's fpcalc 1.5.1 reports the decoder's end of file
+// as "Error decoding audio frame (End of file)" and exits 3 whenever it
+// reaches the end before -length, which is every file shorter than the span
+// asked for. That print covers the whole file, so it is the file's identity.
 //
 // A damaged file can stop at an end of file too. Its DURATION, the length the
 // container declares, is then longer than the span asked for, and it stays a
@@ -475,7 +475,7 @@ func notURLBase64(r rune) bool {
 
 // LookupFingerprint is the compressed fingerprint AcoustID's lookup takes and
 // the file's whole length in seconds, for a file not in the library yet: the
-// import checks a download with it (M502 #5522). IsInconclusive tells a
+// import checks a download with it. IsInconclusive tells a
 // missing or stalled fpcalc from a file it rejected.
 func LookupFingerprint(ctx context.Context, path string) (fingerprint string, durationSec int, err error) {
 	fp, err := computeLookupFingerprint(ctx, path)