docs: sync onboarding runbooks, node inventory, bridge mappings, and box api docs

docs/BRIDGE_SPEC.md

@@ -1,5 +1,7 @@
 # Bridge Spec: Front-Door ↔ muse.ai Side Conversations
 
+> **Box is the main surface.** All operator work goes through Box (box.muse-dev.online). The web UI, `box` CLI, and agents share the same API endpoints. No UI-only powers.
+
 ## Overview
 Metadata bridge (not message relay) linking front-door chat channels
 (muse-dev.online) to muse.ai side conversations. Operators manage via
@@ -96,11 +98,19 @@ bridge remove <bridge_id>
 
 ## Implementation Status
 
-- [ ] `bin/bridge.py` CLI
+- [x] `bin/bridge.py` CLI (exists at `bin/bridge.py`)
 - [ ] `sidechat tag` command in muse-chat-api.py
 - [ ] `sidechat bridge` query command
-- [ ] `bridge/mappings.json` schema
-- [ ] Documentation
+- [x] `bridge/mappings.json` schema (live, 8 mappings as of 2026-10-05)
+- [x] Documentation (this spec)
+
+### P3 reconciliation (2026-10-05, operator-646)
+- Bridge IDs enforced unique per spec (`bridge_id: string (unique)`); duplicate
+  `br-20261003191930` de-duplicated, P2P pair linked via `peer_bridge_id`.
+- Main-loop prompt sidechats for all four agents (646, opm, pip, muse) registered
+  as bridge mappings, so the registry drives the main-loop `prompt_sidechat` map.
+- `peer_bridge_id` (optional): links two ends of a P2P bridge pair. Additive,
+  does not break the v0.1 data model.
 
 ## Notes