feat(fapp): add integration demo + update status

examples/fapp_demo.rs:
- Therapist publishes SlotAnnounce
- Relay caches and handles query
- Patient sends SlotQuery, gets response
- Shows full FappRouter API flow

docs/status.md:
- Updated FAPP integration status
- FappRouter now implemented
- Remaining: multi-node test, SlotReserve/Confirm, LoRa

docs/status.md

@@ -19,19 +19,31 @@
 - Location hint is PLZ only (e.g. "80331") — never exact address
 - Anti-spam: Approbation hash binding, signature verification, sequence-based dedup, rate limiting, TTL enforcement
 
-### FAPP integration — next steps
+### FAPP integration — status
 
-**Current state:** Spec (`docs/specs/fapp-protocol.md`) and Rust module (`crates/quicprochat-p2p/src/fapp.rs`) with store, matching, and tests are in place. **FAPP is not integrated** — `mesh_router.rs` does not decode, route, or emit FAPP CBOR yet.
+**2026-04-01: FappRouter implemented!**
 
-**Next steps**
-1. **Wire into `mesh_router`:** On incoming mesh traffic, recognize FAPP message types; verify signatures and hop rules per spec; update `FappStore`; forward SlotAnnounce/Query/Response where applicable; align with `announce.rs` capability bits (`CAP_FAPP_*`).
-2. **Test on stack:** Multi-node TCP/mesh demo first (two+ nodes, therapist/relay/patient roles); then LoRa hardware when available (airtime, fragmentation, duty cycle).
-3. **After wiring:** SlotReserve/SlotConfirm E2E (e.g. X25519), anonymous return-path for SlotQuery responses, per-therapist rate limits in `FappStore`.
+New `fapp_router.rs` module:
+- `FappAction` enum: Ignore, Dropped, Forward, QueryResponse
+- Wire format: 1-byte tag (0x01-0x05) + CBOR body
+- `FappRouter` struct with shared `RoutingTable` + `TransportManager`
+- `handle_incoming()` decodes and dispatches FAPP frames
+- `process_slot_announce()` with relay/flood logic (dedup, hop check, store, forward)
+- `process_slot_query()` answers from local `FappStore`
+- `broadcast_announce()` / `send_query()` for outbound floods
+- `drain_pending_sends()` for async send integration
+- 3 unit tests passing
+
+**Remaining steps**
+1. **Integration test:** Multi-node demo (therapist → relay → patient flow)
+2. **Wire to P2pNode:** Add `FappRouter` to `start_with_mesh()` or similar
+3. **SlotReserve/SlotConfirm:** E2E encrypted reservation flow
+4. **LoRa test:** Verify FAPP over constrained links
 
 **Definition of done**
-- Router end-to-end path for FAPP matches spec (verify, dedup, TTL, forwarding semantics).
-- Integration proof: announce → query → response over at least one multi-hop path (automated test or documented manual run).
-- Hardware check: same scenario on LoRa, or a short note in status on what blocked it.
+- announce → query → response works over multi-hop (automated or manual)
+- SlotReserve/Confirm E2E encryption works
+- LoRa test or documented blocker
 
 ---