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/admin_requests_test.go

@@ -55,8 +55,9 @@ func seedPendingArtistRequest(t *testing.T, h *handlers, user dbq.User, artistMB
 	return createArtistRequest(t, h, user, artistMBID, artistName)
 }
 
-// TestHandleListAdminRequests_DefaultStatus_Pending seeds 2 pending + 1 rejected
-// and verifies that GET without ?status returns only the 2 pending rows.
+// TestHandleListAdminRequests_DefaultStatus_Pending seeds 2 pending + 1
+// rejected and verifies that GET without ?status returns only the 2 pending
+// rows.
 func TestHandleListAdminRequests_DefaultStatus_Pending(t *testing.T) {
 	h, _ := testHandlers(t)
 	resetRequests(t, h)
@@ -96,8 +97,8 @@ func TestHandleListAdminRequests_DefaultStatus_Pending(t *testing.T) {
 	}
 }
 
-// TestHandleListAdminRequests_StatusFilter verifies GET ?status=rejected returns
-// only rejected rows.
+// TestHandleListAdminRequests_StatusFilter verifies GET ?status=rejected
+// returns only rejected rows.
 func TestHandleListAdminRequests_StatusFilter(t *testing.T) {
 	h, _ := testHandlers(t)
 	resetRequests(t, h)