fix: tighten version parsing, propagate HMAC sign failure, add deployment docs

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

server/ota_endpoint.py

@@ -2,18 +2,29 @@
 """
 OTA firmware update endpoints.
 
-To register in the server main app:
-    from server.ota_endpoint import router as ota_router
-    app.include_router(ota_router)
+Deployment workflow:
+  1. Generate signing key (one-time):
+       python tools/gen_signing_key.py
+     → secrets/firmware_signing_key.pem (keep offline)
+     → firmware/lib/ota_updater/ota_pubkey.h (commit this)
 
-Route handlers have HMAC auth commented out pending import-path confirmation:
-    from .main import verify_device_hmac  # adjust to actual module
-Then uncomment the Depends lines in ota_check() and ota_firmware().
+  2. Build and deploy a new firmware version:
+       pio run -e timercam                    # build
+       python tools/deploy_firmware.py \\
+         firmware/.pio/build/timercam/firmware.bin 1.2.3
+     → server/firmware/ updated with current.bin, current.sig, manifest.json
 
-Firmware artifacts expected under FIRMWARE_DIR (default: server/firmware/):
-    current.bin   — raw firmware binary
-    current.sig   — 64-byte r‖s Ed25519/ECDSA signature
-    manifest.json — {"version": "X.Y.Z", "size": N, "sha256": "hex..."}
+  3. Bump FW_VERSION in firmware/include/version.h before each release.
+
+  4. Register in server main app:
+       from server.ota_endpoint import router as ota_router
+       app.include_router(ota_router)
+     Also uncomment Depends(verify_device_hmac) on both route handlers
+     and confirm the HMAC format matches hmac.cpp:
+       method + "\\n" + path + "\\n" + timestamp + "\\n" + sha256_hex(body)
+
+Note: HMAC auth is currently commented out on route handlers — must be wired
+before production use. verify_device_hmac must use the same format as hmac.cpp.
 """
 import base64
 import json
@@ -35,6 +46,8 @@ def _parse_version(v: str) -> tuple:
     """Parse semver string to comparable tuple; returns (0,0,0) on malformed input."""
     try:
         parts = v.strip().split(".")
+        if len(parts) != 3:
+            return (0, 0, 0)
         return tuple(int(x) for x in parts)
     except (ValueError, AttributeError):
         return (0, 0, 0)