fix: Remove Matrix integration — notifications move to forge + OpenClaw (#732)

Remove all Matrix/Dendrite infrastructure:
- Delete lib/matrix_listener.sh (long-poll daemon), lib/matrix_listener.service
  (systemd unit), lib/hooks/on-stop-matrix.sh (response streaming hook)
- Remove matrix_send() and matrix_send_ctx() from lib/env.sh
- Remove MATRIX_HOMESERVER auto-detection, MATRIX_THREAD_MAP from lib/env.sh
- Remove [matrix] section parsing from lib/load-project.sh
- Remove Matrix hook installation from lib/agent-session.sh
- Remove notify/notify_ctx helpers and Matrix thread tracking from
  dev/dev-agent.sh and action/action-agent.sh
- Remove all matrix_send calls from dev-poll.sh, phase-handler.sh,
  action-poll.sh, vault-poll.sh, vault-fire.sh, vault-reject.sh,
  review-poll.sh, review-pr.sh, supervisor-poll.sh, formula-session.sh
- Remove Matrix listener startup from docker/agents/entrypoint.sh
- Remove append_dendrite_compose() and setup_matrix() from bin/disinto
- Remove --matrix flag from disinto init
- Clean Matrix references from .env.example, projects/*.toml.example,
  formulas/*.toml, AGENTS.md, BOOTSTRAP.md, README.md, RESOURCES.md,
  PHASE-PROTOCOL.md, and all agent AGENTS.md/PROMPT.md files

Status visibility now via Codeberg PR/issue activity. Human interaction
via vault items through forge. Proactive alerts via OpenClaw heartbeats.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

README.md

@@ -40,10 +40,6 @@ cron (weekly) ──→ planner-poll.sh  ← gap-analyse VISION.md, create backl
 cron (*/30) ──→ vault-poll.sh    ← safety gate for dangerous/irreversible actions
                  └── claude -p: classify → auto-approve/reject or escalate
 
-systemd ──→ matrix_listener.sh   ← long-poll daemon for human replies
-              └── dispatches thread replies → supervisor/gardener/dev/review/vault
-
-all agents ──→ matrix_send()     ← status updates, escalations, merge notifications
 ```
 
 ## Prerequisites
@@ -58,7 +54,6 @@ all agents ──→ matrix_send()     ← status updates, escalations, merge no
 
 **Optional:**
 
-- [Matrix](https://matrix.org/) homeserver ([Dendrite](https://github.com/matrix-org/dendrite) or Synapse) — real-time notifications, escalation threads with human-in-the-loop replies
 - [Foundry](https://getfoundry.sh/) (`forge`, `cast`, `anvil`) — only needed if your target project uses Solidity
 - [Node.js](https://nodejs.org/) — only needed if your target project uses Node
 
@@ -115,10 +110,8 @@ disinto/
 ├── .env.example          # Template — copy to .env, add secrets + project config
 ├── .gitignore            # Excludes .env, logs, state files
 ├── lib/
-│   ├── env.sh              # Shared: load .env, PATH, API helpers, matrix_send()
-│   ├── ci-debug.sh         # Woodpecker CI log/failure helper
-│   ├── matrix_listener.sh  # Matrix long-poll daemon (dispatches replies)
-│   └── matrix_listener.service  # systemd unit for the listener
+│   ├── env.sh              # Shared: load .env, PATH, API helpers
+│   └── ci-debug.sh         # Woodpecker CI log/failure helper
 ├── dev/
 │   ├── dev-poll.sh       # Cron entry: find ready issues
 │   └── dev-agent.sh      # Implementation agent (claude -p)