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>

supervisor/supervisor-poll.sh

@@ -134,11 +134,9 @@ if [ "${AVAIL_MB:-9999}" -lt 500 ] || { [ "${SWAP_USED_MB:-0}" -gt 3000 ] && [ "
   fi
 fi
 
-# P0 is urgent — send immediately before per-project checks can crash the script
+# P0 alerts already logged — clear so they are not duplicated in the final consolidated log
 if [ -n "$P0_ALERTS" ]; then
-  matrix_send "supervisor" "🚨 Supervisor P0 alerts:
-$(printf '%b' "$P0_ALERTS")" 2>/dev/null || true
-  P0_ALERTS=""  # clear so it is not duplicated in the final consolidated send
+  P0_ALERTS=""
 fi
 
 # =============================================================================
@@ -184,11 +182,9 @@ if [ "${DISK_PERCENT:-0}" -gt 80 ]; then
   fi
 fi
 
-# P1 is urgent — send immediately before per-project checks can crash the script
+# P1 alerts already logged — clear so they are not duplicated in the final consolidated log
 if [ -n "$P1_ALERTS" ]; then
-  matrix_send "supervisor" "⚠️ Supervisor P1 alerts:
-$(printf '%b' "$P1_ALERTS")" 2>/dev/null || true
-  P1_ALERTS=""  # clear so it is not duplicated in the final consolidated send
+  P1_ALERTS=""
 fi
 
 # Emit infra metric
@@ -618,7 +614,6 @@ Instructions:
         _nh_renotify="/tmp/dev-renotify-${proj_name}-${_nh_issue}"
         if [ ! -f "$_nh_renotify" ]; then
           _nh_age_h=$(( _nh_age / 3600 ))
-          matrix_send "dev" "⏰ Reminder: Issue #${_nh_issue} still needs human input (waiting ${_nh_age_h}h)" 2>/dev/null || true
           touch "$_nh_renotify"
           flog "${proj_name}: #${_nh_issue} re-notified (escalate for ${_nh_age_h}h)"
         fi
@@ -785,10 +780,6 @@ ALL_ALERTS="${P0_ALERTS}${P1_ALERTS}${P2_ALERTS}${P3_ALERTS}${P4_ALERTS}"
 if [ -n "$ALL_ALERTS" ]; then
   ALERT_TEXT=$(echo -e "$ALL_ALERTS")
 
-  # Notify Matrix
-  matrix_send "supervisor" "⚠️ Supervisor alerts:
-${ALERT_TEXT}" 2>/dev/null || true
-
   flog "Invoking claude -p for alerts"
 
   CLAUDE_PROMPT="$(cat "$PROMPT_FILE" 2>/dev/null || echo "You are a supervisor agent. Fix the issue below.")