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/api/file_remove_error.go

@@ -10,17 +10,17 @@ import (
 	"git.fabledsword.com/bvandeusen/minstrel/internal/library"
 )
 
-// fileRemoveAPIError answers a delete that could not reach the track's file
-// (#3918). Both delete endpoints use it, so the operator gets the same
+// fileRemoveAPIError answers a delete that could not reach the track's file.
+// Both delete endpoints use it, so an admin gets the same
 // explanation from the admin remove-track action and from quarantine's Delete
 // file.
 //
 // The unwritable case is a 409 rather than a 500 because nothing is broken: the
 // request conflicts with how the library is mounted, and the fix is the
-// operator's. The message names the directory — removal writes to the parent,
+// host's. The message names the directory — removal writes to the parent,
 // not the file — and the uid/gid the process runs as, which is the half of a
 // permission problem invisible from the host. Every case says nothing was
-// deleted, because that is exactly what the operator will be worried about.
+// deleted, because that is exactly what an admin will be worried about.
 func fileRemoveAPIError(err error) (*apierror.Error, bool) {
 	var fre *library.FileRemoveError
 	if !errors.As(err, &fre) {
@@ -46,7 +46,7 @@ func fileRemoveAPIError(err error) (*apierror.Error, bool) {
 }
 
 // logFileRemoveFailure records a delete that could not reach its file. An
-// unwritable library is an environment fact the operator can fix, so it is a
+// unwritable library is an environment fact an admin can fix, so it is a
 // Warn; anything else is a real fault.
 func logFileRemoveFailure(logger *slog.Logger, apiErr *apierror.Error, attrs ...any) {
 	attrs = append(attrs, "code", apiErr.Code, "err", apiErr.Cause)