docs: stage-0 coherence pass across README/HANDOFF/recorder/research

- README: recorder row + architecture diagram reflect fold->parquet->
  15-min mirror (and research/ joins the diagram); cheat-sheet gains a
  'sync the tape now' row
- HANDOFF: snapshot dated 2026-07-21, launchd roster (tape-sync +
  research-nightly wait behavior), #15 back in the open queue, tape ops
  line in quick-reference
- recorder/README: ops block (sync_tape + fold health, deploy gap note),
  storage economics (/mo, mirror as Stage-1 feedstock)
- research/README: nightly.sh wait-for-fresh-tape semantics
- live/tape_sharps.json: refreshed 4-day chain-validated screen (the
  smoke run had briefly left a chain-less version)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

research/README.md

@@ -28,4 +28,6 @@ Layout:
   requote.py       crater→requote timing measurement (retry tuning)
   forward.py       scores frozen studies on new tape days → forward_ledger.jsonl
   params/          frozen study parameters (committed = frozen)
-  nightly.sh       manual/launchd runner (separate from daily.sh)
+  nightly.sh       launchd runner (fires 09:15, then WAITS for fresh tape —
+                   Stage 0 keeps the tape ~15-min fresh whenever the Mac is
+                   awake; deadline 8h, then scores anyway and logs staleness)