TODO.d: capture-the-moment design, stems ring, hands and code in one bundle

TODO.d/2026-11-01-moment-capture.md

+# Capture the moment: stems + hands + code, saved after the fact (2026-11-01)
+
+Owner's wish: do not ask "record?", ask "keep what just happened". After a good stretch,
+`moment last 30m` must leave a bundle from which that stretch can be reconstructed:
+every stem (the keyboard included), every MIDI press, and the exact code that was
+playing. The stereo black box already works that way; nothing else does yet.
+
+## Where the rig stands (measured 2026-11-01)
+
+- **Stereo black box**: always on, opus, ~67 MB/h, hourly segments, `gig_record.sh slice`
+  cuts one segment by hand. Follows Ardour Master's sink. No stems, no code, no MIDI.
+- **Ardour stems**: only while a track is armed AND the transport rolls (`take-rec arm`).
+  Nothing written since Take109 (2026-09-28). `Keys` has NEVER produced a stem file in any
+  take; `take-rec` only knows `Tidal NN` (`take-lens.SRC_RE`), so `Keys` and `Mic` fall
+  outside arm, verify and `take-master`. Float32 WAV costs ~17 GB/h (Take109: 2.9 GB for
+  10 min), so "always roll Ardour" is out: 161 GB free, 92% full.
+- **gig-log** already records: `eval` (path + dN names, from `eval-events.jsonl` written by
+  the Pulsar package), `track`, `cc` (coalesced 1 Hz), `health`, `mark`, system samples.
+  It supports `note` events at full resolution, but its MIDI lens binds ONE port (the
+  LCXL3), so the KeyStep's presses are not logged (0 `note` rows in today's log).
+  `eval` carries no code, no commit, no file hash.
+
+## Shape
+
+1. **Stem ring** (new unit, e.g. `gig-stems`): taps the orbit outputs of SuperCollider plus
+   `ardour:Keys` and `ardour:Mic` (when Ardour is up), writes lossless FLAC per orbit in
+   short segments, and deletes anything older than the window (default 45 min, hard cap in
+   GB). Independent of Ardour, so it works dawless. Ardour's own take path stays for
+   deliberate full-quality takes.
+2. **Hands**: a second MIDI lens in gig-log for the KeyStep, notes at full resolution.
+3. **Code**: each `eval` record gains `rev` (git HEAD), `dirty`, and `sha` of the file, with
+   the bytes stored once per sha in a code store. Exact block text needs the Pulsar package
+   to send it (the file on disk can lag the buffer): a later step, said out loud in the
+   manifest until then.
+4. **`moment`**: `moment last 30m [name]` / `moment since HH:MM`. Resolves the window, then
+   writes one bundle outside any prune: stem slices (cut across segments), stereo slice,
+   the gig-log lines of the window, the evals' code blobs and `git rev`, and a manifest
+   (window, what was present, what was missing, sizes).
+5. **Button**: Bridge/tray "Save last 30 min"; maybe an LCXL3 pad later.
+
+## Order and acceptance
+
+0. **Measure the ring first** (before any mechanism): FLAC MB/min, CPU %, xruns over
+   10 min of real playing, on the fan-sensitive laptop. No ring unit until this is written
+   down. Disk rule: bounded by construction, report anything over 500 MB.
+1. **KeyStep lens**: tiny change; accept = notes from the KeyStep appear in the log with
+   `p` = its port, survive a replug (like the LCXL3 lens).
+2. **Eval enrichment** (`rev`, `dirty`, `sha`, code store); accept = a past eval can be
+   rebuilt to the exact file bytes.
+3. **Arm/verify/summary/master learn `Keys` and `Mic`** (by track name, not orbit number);
+   accept = a real roll produces a Keys stem and `verify` says so. Arm uses strip ids
+   guessed from the XML route order, never confirmed by a live roll: confirm it.
+4. **Ring unit**; accept = after 20 min of playing, the ring holds the last N minutes of
+   every stem, silence in none of the live ones, and size stays under the cap.
+5. **`moment`** with a manifest; accept = from a clean state, `moment last 10m` yields a
+   bundle whose stems line up with the stereo slice (sample offset reported).
+6. Button.
+
+## Open questions
+
+- How to tap 28+ ports cheaply: one `pw-record`/jack client per pair vs one multichannel
+  capture split by ffmpeg. Phase 0 decides by measurement.
+- FLAC is 24-bit; SuperCollider output is float and could exceed 0 dBFS. Check peaks, or
+  use a float container for the ring.
+- Window length N and the hard cap (disk floor is 25 GB, 100 GB is the keep-scratch line).