fix(calibration): address PR review — aarch64 decouple, API auth, path traversal, throttle

Resolves the review on #989:

- **Cross-compile (the appliance blocker):** make wifi-densepose-mat optional
  and feature-gate it (`mat`), so `cargo build -p wifi-densepose-cli
  --no-default-features` excludes the mat→nn→ort(ONNX)→openssl-sys chain.
  Verified: `cargo tree --no-default-features` shows 0 ort/openssl deps →
  calibration cross-compiles clean for the Pi.
- **Security (must-fix before LAN):**
  - `--token` / CALIBRATE_TOKEN bearer-auth middleware on every route; warns if
    bound non-loopback without a token.
  - sanitize client-supplied `room_id` to [A-Za-z0-9_-] (≤64) before it reaches
    the baseline write path — kills the `../` file-write primitive. + test.
- **Perf:** stop locking shared status + cloning SessionStatus on every UDP
  frame — counters/snapshot flush on the 200 ms tick instead (no CPU
  starvation under flood). finalize write moved to async `tokio::fs::write`.
- **Docs:** ADR-151 STALE wording matches the impl (baseline-id change;
  drift-threshold = P6 refinement); integration doc gets the
  `--no-default-features` build + auth/sanitize notes.

35 calibration + 15 CLI tests (no-default) / 20 CLI (default) pass.

Co-Authored-By: claude-flow <ruv@ruv.net>

docs/integration/calibration-appliance-integration.md

@@ -170,7 +170,16 @@ Pure Rust; deps are `wifi-densepose-core` + `wifi-densepose-signal` (default-fea
 Verified on `cognitum-v0`: aarch64, `cargo 1.96.0`, Hailo `HAILO10H`, `ruview-vitals-worker:50054`.
 
 **Step 1 — vendor / depend on the crate.** Add `wifi-densepose-calibration` (path or published crate)
-to the appliance workspace. It builds natively (aarch64, no BLAS/GPU).
+to the appliance workspace. It builds natively on aarch64 — no BLAS/GPU, **and no ONNX/OpenSSL**:
+the CLI's `mat`→`nn`→`ort`(ONNX)→`openssl-sys` chain is now feature-gated out of the calibration build.
+
+```bash
+# Pi/appliance calibration binary — cross-compiles clean (no ort/openssl):
+cargo build -p wifi-densepose-cli --no-default-features --release
+#   (omit `--no-default-features` only if you also need the MAT subcommands)
+```
+Verified: `cargo tree -p wifi-densepose-cli --no-default-features` shows **0** `ort`/`openssl-sys` deps;
+`cross test --target aarch64-unknown-linux-gnu` passes the calibration suite under qemu.
 
 **Step 2 — wire the CSI source.** Two options:
   - (a) Tee the ESP32 UDP stream the vitals worker already receives into the calibration ingest, or
@@ -191,8 +200,13 @@ head to Hailo HEF, serve via `ruvector-hailo-worker:50051`; the small specialist
 embedding. This is the ADR-150 follow-on — *not required* for the calibration service to run.
 
 **Privacy / security:** keep baselines + banks local; if federating across appliances (ADR-105),
-exchange bank/model deltas, never raw CSI. `calibrate-serve` CORS is permissive for dev — bind to
-loopback and gate via the appliance proxy in production.
+exchange bank/model deltas, never raw CSI. Hardening already in place:
+- **`--token <T>`** (or `CALIBRATE_TOKEN` env) requires `Authorization: Bearer <T>` on every route; the
+  server warns loudly if bound to a non-loopback address without a token.
+- **`room_id` is sanitized** to `[A-Za-z0-9_-]` (≤64 chars) before it touches the baseline write path —
+  no `../` / absolute-path traversal.
+- CORS is permissive for dev — in production bind to loopback and reverse-proxy through the appliance
+  gateway (which already enforces bearer auth).
 
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