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/me_test.go

@@ -37,13 +37,10 @@ func TestHandleGetMe_ReturnsAuthenticatedUser(t *testing.T) {
 	}
 }
 
-// Drift #578 regression guard: a user whose profile fields ARE set
-// must see them in the /api/me response. Previously this handler
-// emitted the narrower UserView so Android Settings → Profile saw
-// display_name=null and email=null on every read, wiped the form
-// fields, and submitting from that blank state destroyed the user's
-// stored values via the "empty string clears to NULL" semantics of
-// PUT /api/me/profile.
+// A user whose profile fields ARE set must see them in the /api/me
+// response: a Settings → Profile form seeded without them would, on save,
+// clear the stored values through PUT /api/me/profile's "empty string
+// clears to NULL".
 func TestHandleGetMe_IncludesDisplayNameAndEmail(t *testing.T) {
 	h, pool := testHandlers(t)
 	user := seedUser(t, pool, "alice", "hunter2", false)