feat: agent-to-agent platform on ZeroClaw 0.8.2 — rooms, delegation, A2A ingress

Builds on the v0.8.2 runtime. Four workstreams, all behind the §15 MCP door:

- Group rooms (Phase 1): migration 0026; N-way threads repo with a DM/room
  count-guard; chat.send {room} + room.create/invite/leave tools; RoomMessage
  -> room.message SSE; /api/claw-chat/rooms* APIs; Observer room badge.
- Per-claw door identity: door caller_agent resolves the X-ZeroClaw-Agent
  header (set by the fork) to the specific claw, falling back to roster[0].
- Gated delegation bridge (Phase 3): clawmates__delegate door tool drives a
  sibling via the existing /ws/chat ZeroClawDriveExecutor (not A2A); self-deny,
  per-workspace hourly budget, audit trail, untrusted-banner result. Native
  in-daemon delegation stays off (it would bypass the door).
- A2A tenant ingress (Phase 2): migration 0027 (workspace_a2a + a2a_tokens);
  runtime_provision enable_a2a_server/publish_claw; routes/a2a.rs tenant-aware
  proxy (per-workspace tokens, injected internal bearer, daemon stays internal,
  cards URL-rewritten to the cm-api edge); a2a.invoked taxonomy.

Tests: cm-db room repos, cm-runtime chat tools, door units. sqlx cache updated.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

.sqlx/query-58d9a07a599761cd9ba2440b1868d96f78db918b603ff04dea64339be08a39c3.json

@@ -0,0 +1,70 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "SELECT t.id, t.workspace_id, t.subject, t.sensitivity, t.kind,\n                  t.created_by, t.created_at,\n                  ARRAY(SELECT p2.agent_id FROM thread_participants p2\n                        WHERE p2.thread_id = t.id AND p2.active) AS \"participants!\",\n                  (SELECT m.content->>'text' FROM thread_messages m\n                   WHERE m.thread_id = t.id\n                   ORDER BY m.created_at DESC LIMIT 1) AS last_preview\n           FROM threads t\n           WHERE t.workspace_id = $1 AND t.kind = 'room'\n           ORDER BY (SELECT max(m.created_at) FROM thread_messages m\n                     WHERE m.thread_id = t.id) DESC NULLS LAST",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "id",
+        "type_info": "Uuid"
+      },
+      {
+        "ordinal": 1,
+        "name": "workspace_id",
+        "type_info": "Uuid"
+      },
+      {
+        "ordinal": 2,
+        "name": "subject",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 3,
+        "name": "sensitivity",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 4,
+        "name": "kind",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 5,
+        "name": "created_by",
+        "type_info": "Uuid"
+      },
+      {
+        "ordinal": 6,
+        "name": "created_at",
+        "type_info": "Timestamptz"
+      },
+      {
+        "ordinal": 7,
+        "name": "participants!",
+        "type_info": "UuidArray"
+      },
+      {
+        "ordinal": 8,
+        "name": "last_preview",
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Left": [
+        "Uuid"
+      ]
+    },
+    "nullable": [
+      false,
+      false,
+      false,
+      false,
+      false,
+      true,
+      false,
+      null,
+      null
+    ]
+  },
+  "hash": "58d9a07a599761cd9ba2440b1868d96f78db918b603ff04dea64339be08a39c3"
+}