docs: api comments say what the endpoints do, not how they came to be (#6277)

Rewrites the internal/api comment blocks to rule 32: task, milestone and
rule ids gone, the stories behind them restated as the constraint they
left, stale references corrected (the stream secret is wired from config,
the timezone handler already refreshes the scheduler, the Android app is
the native client, the design docs cited are not in the repo). Also
rewraps comment lines over 80 columns left by the earlier batches.

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

internal/config/config.go

@@ -112,9 +112,10 @@ func Default() Config {
 			RadioSizeMax:        200,
 		},
 		Library: LibraryConfig{
-			// On by default so a fresh install populates its library on
-			// first boot with no manual step. Scans are incremental (unchanged files skipped by
-			// mtime), so every later restart is just a cheap directory walk.
+			// On by default so a fresh install populates its library on first
+			// boot with no manual step. Scans are incremental (unchanged files
+			// skipped by mtime), so every later restart is just a cheap
+			// directory walk.
 			ScanOnStartup:     true,
 			CoverArtFromMBCAA: true,
 		},
@@ -151,13 +152,15 @@ const streamSecretBytes = 64
 const streamSecretFile = "stream_secret"
 
 // resolveStreamSecret populates cfg.StreamSecret using, in order:
-//  1. MINSTREL_STREAM_SECRET env var (base64-url encoded — accepts either padded or raw form).
+//  1. MINSTREL_STREAM_SECRET env var (base64-url encoded — accepts either
+//     padded or raw form).
 //  2. <Storage.DataDir>/stream_secret if present (auto-generated on a
 //     previous boot; survives restarts so signed URLs stay valid).
 //  3. Auto-generate streamSecretBytes random bytes, persist them to that
 //     file at 0600, then use them.
 //
-// Logs (only) when an auto-generation happens, so it shows on first boot. Never logs the contents.
+// Logs (only) when an auto-generation happens, so it shows on first boot. Never
+// logs the contents.
 //
 // The loader runs before slog is initialized in cmd/minstrel/main.go;
 // log.Printf is the project's pre-logger convention.