docs: record Phase 7 resilience state and re-scope

.agents/MEMORY.md

@@ -71,6 +71,22 @@ loopback; current phase is Phase 7.
   No application changes needed — the receiver already announces on all
   interfaces. nmcli property syntax validated against NM 1.58 with a
   disposable profile; AP bring-up itself can only be validated on the Pi.
+- **Phase 7 resilience shipped** (pending Pi-side hw-decode run):
+  - PLI over signaling: `SessionPli` message; the depacketizer now returns
+    `DepacketizeResult{access_unit, frame_dropped}`; the receiver
+    rate-limits PLIs to 1/500 ms; the sender keeps the signaling channel
+    open and calls `SenderPipeline::request_keyframe()` (thread-safe
+    atomic → run-loop → encoder). Validated end-to-end with a probe that
+    drops a mid-keyframe packet: receiver logs "frame damaged",
+    PLI arrives with the session id.
+  - `RtpJitterBuffer` (rtp_packet.h): sequence reordering, 16 pkt/60 ms,
+    straggler discard via serial-number arithmetic, overflow flush for
+    genuine loss. Zero added latency on in-order streams.
+  - Hardware decode probe in DecoderFactory (`DecoderConfig.hardware_accel`,
+    default true): h264_v4l2m2m first, software fallback, `--swdecode` opts
+    out. On the desktop the probe fails cleanly ("Could not find a valid
+    device") and falls back; on the Pi it should pick the VideoCore m2m
+    device — NEEDS THE USER'S PI RUN to confirm.
 - **REAL-HARDWARE VALIDATION (desktop → Pi Zero 2 W over Wi-Fi)**: the full
   chain works on two machines: mDNS discovery → signaling negotiation →
   RTP over Wi-Fi → software H.264 decode → fullscreen KMSDRM letterboxed