Video calls (PairUX→ASCII), agent@ chat, and finger routes

ssh video-<code>@ joins a PairUX/LiveKit call rendered as truecolor
ASCII (▀ half-blocks, 2 pixels per cell); video@ prompts for a code.
Codes are minted by PairUX only. Pipeline: VP8 RTP → PLI keyframe
requests → ivfwriter remux → ffmpeg decode/scale → RGB24 → ANSI →
bubbletea over the SSH PTY. Subscriber-only, no audio in v1.

ssh agent@ opens a persisted chat with the operator's agent —
AGENTBBS_AGENT_CMD runs per message (stdin→stdout), e.g. `claude -p`.

ssh <member>@ with someone else's name prints a classic finger card
(.plan, member since, last seen) and disconnects; your own name still
enters the hub.

cmd/lkpublish: dev publisher for testing (explicit -fps pacing; lksdk
IVF replay mispaces from file timebase alone, measured 1fps from a
15fps file; dimensions required or dynacast pauses the track).

Verified end-to-end against livekit-server --dev: 128k truecolor cells
/ 20k distinct colors streamed over a real SSH session; chat round-trip
and finger card verified over SSH. Go toolchain pinned to 1.26 via
mise.toml (lksdk requirement).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/video.md

@@ -0,0 +1,64 @@
+# Video Calls Addendum (PairUX over SSH)
+
+Join a PairUX video call from a terminal: the platform subscribes to the
+call's LiveKit room and renders participant video as **truecolor ASCII** —
+each character cell is two pixels via the upper-half block (▀), the same
+technique doom-ascii uses.
+
+## SSH routes
+
+| Command | What happens |
+|---|---|
+| `ssh video-<code>@profullstack.com` | join call `<code>` directly |
+| `ssh video@profullstack.com` | prompted for a code |
+
+**Codes are minted by PairUX.** The SSH surface never creates calls — to
+start one you must already have a code (create the call in PairUX first).
+
+## Pipeline
+
+```
+PairUX / LiveKit room
+   └─ VP8 RTP track  ── PLI keyframe requests ──┐
+        └─ ivfwriter remux → ffmpeg (decode + scale) → RGB24 frames
+             └─ half-block ANSI (internal/ascii) → bubbletea → SSH PTY
+```
+
+- Subscriber-only: the terminal viewer publishes nothing.
+- A PLI is sent on subscribe and every 2s — without it the SFU never starts
+  forwarding video to a fresh subscriber, and the periodic refresh bounds
+  packet-loss artifacts.
+- Audio is not rendered (it's a terminal); v2 could downlink Opus → local
+  audio out for desktop SSH clients.
+- Frame size locks to the terminal geometry at join (`scale=` in ffmpeg);
+  ~10–15 fps at typical terminal sizes costs a few hundred KB/s of SSH
+  bandwidth.
+
+## Configuration
+
+Shares PairUX's env shape:
+
+| Var | Meaning |
+|---|---|
+| `AGENTBBS_LIVEKIT_URL` (or `LIVEKIT_URL` / `NEXT_PUBLIC_LIVEKIT_URL`) | LiveKit ws URL |
+| `AGENTBBS_LIVEKIT_KEY` (or `LIVEKIT_API_KEY`) | API key |
+| `AGENTBBS_LIVEKIT_SECRET` (or `LIVEKIT_API_SECRET`) | API secret |
+| `AGENTBBS_VIDEO_DEBUG` | dump the received IVF stream to this path |
+
+Unconfigured hosts refuse with a clear message.
+
+## Dev testing
+
+```bash
+docker run -d -p 7880:7880 -p 7881:7881 -p 7882:7882/udp \
+  livekit/livekit-server --dev --bind 0.0.0.0   # devkey/secret
+ffmpeg -f lavfi -i testsrc=size=320x240:rate=15 -t 900 \
+  -c:v libvpx -b:v 400k -g 15 -y test.ivf
+go run ./cmd/lkpublish -room demo1 -fps 15 -file test.ivf
+ssh -p 2222 video-demo1@localhost
+```
+
+Note: `lkpublish` passes an explicit frame duration — lksdk's IVF replay
+pacing can't be trusted from the file timebase alone (we measured 1fps from
+a 15fps file without it). Real PairUX publishers are browsers, which pace
+correctly on their own.