refactor: remove unused cross-agent-comms subsystem

Nothing used the cross-agent message system (send/recv/watch/status/discover/halt/resume over the inbox/from-agents/ file-IPC protocol). Every cross-project handoff goes through inbox-send instead. I removed the scripts, READMEs, workflow, tests, INDEX entry, the three startup.org wirings, and the legacy bin symlinks, then repointed helper-mode's escalation to inbox-send and noted the removal in the generic-agent-runtime spec.

1 files changed, 0 insertions, 117 deletions

diff --git a/.ai/scripts/cross-agent-comms/cross-agent-resume.md b/.ai/scripts/cross-agent-comms/cross-agent-resume.md
deleted file mode 100644
index 8aa8357..0000000
--- a/.ai/scripts/cross-agent-comms/cross-agent-resume.md
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-# cross-agent-resume
-
-**Purpose.** Clear the HALT file and restart the watcher service. Counterpart
-to `cross-agent-halt`. Resuming agent polling is **explicit per-session** —
-this script doesn't auto-revive halted polling loops; you tell each session
-to re-engage.
-
-## Usage
-
-```
-cross-agent-resume [--tailnet]
-```
-
-### Flags
-
-| Flag | Default | Purpose |
-|---|---|---|
-| `--tailnet` | local only | Clear HALT on every peer in `peers.toml` via SSH over Tailscale. |
-
-## Behavior
-
-### Local resume (default)
-
-1. Remove the HALT file: `rm -f ~/.config/cross-agent-comms/HALT`. (Use `-f`
-   so a missing file isn't an error — running resume when not halted is safe.)
-2. Restart the watcher service: `systemctl --user start cross-agent-watch.path`.
-3. Print a summary:
-   ```
-   ✓ HALT file removed
-   ✓ Watcher service started (cross-agent-watch.path)
-   - cross-agent-send and cross-agent-recv will accept new operations.
-   - Inbound messages held during halt will be picked up by the watcher.
-   - Agent polling does NOT auto-resume. To re-engage polling in a paused
-     session, open that Claude session and tell the agent to resume.
-   ```
-4. Exit 0.
-
-### Cross-tailnet resume (`--tailnet`)
-
-1. Apply local resume steps 1-2 first.
-2. Read `peers.toml` for the list of remote machines.
-3. For each peer, SSH:
-   ```
-   ssh <user>@<host> "rm -f ~/.config/cross-agent-comms/HALT && \
-                       systemctl --user start cross-agent-watch.path"
-   ```
-4. Track per-peer success/failure:
-   ```
-   Resuming velox.local       ✓ (HALT cleared, watcher started)
-   Resuming bastion.local     ✗ (ssh exit 255: no route to host)
-   Resuming locally           ✓
-
-   PARTIAL RESUME: 2/3 machines resumed. bastion.local still halted.
-   ```
-5. Exit 0 if all peers resumed; exit 1 on any failure.
-
-## Why agent polling doesn't auto-resume
-
-Two reasons the asymmetry is deliberate:
-
-1. *Auto-resume could silently invert intentional kills.* If you halted
-   because a session was misbehaving, removing HALT shouldn't quietly revive
-   that session's polling. You re-engage explicitly so you're aware of which
-   sessions came back online.
-
-2. *You may want to inspect before resuming.* After a halt, you might want to
-   read pending messages, fix configuration, or kill a particular Claude
-   session entirely. Per-session resume forces that pause.
-
-## Re-engaging polling in a Claude session
-
-After `cross-agent-resume`, open the relevant Claude session and say something
-like:
-
-```
-HALT is cleared; resume polling.
-```
-
-The agent will check the HALT file (now absent), re-create its polling
-schedule, and continue the in-flight conversation from wherever it left off.
-The conversation file is intact; the receiver will pick up any new messages
-that arrived during the halt window.
-
-## Failure modes
-
-| Symptom | Cause | Fix |
-|---|---|---|
-| HALT file doesn't exist | Already resumed (or never halted) | OK — `-f` makes this a no-op. |
-| `systemctl --user start` fails | Watcher service not installed | Install per `cross-agent-watch.md`'s systemd recipe. |
-| `--tailnet` resumes some peers but not others | Same as halt: peer unreachable | Per-peer status reported; resolve manually for unreachable peers. |
-| Permission denied removing HALT file | File owned by another user | Check ownership; HALT files should be owned by the running user. |
-
-## Examples
-
-```bash
-# Local resume after a halt
-cross-agent-resume
-
-# Resume all tailnet peers + local
-cross-agent-resume --tailnet
-```
-
-## Recovery flow
-
-After a halt:
-
-1. Investigate whatever caused the halt (runaway loop, bad config, etc.).
-2. Fix the underlying issue.
-3. Run `cross-agent-resume`.
-4. Open each Claude session that was polling and tell its agent to re-engage.
-5. Confirm operation with `cross-agent-status`.
-
-## See also
-
-- `cross-agent-halt` — counterpart that creates the HALT file.
-- `cross-agent-status` — verify HALT cleared and see pending messages.
-- `cross-agent-comms.org` — protocol spec, `* Halt mechanism` section.