feat(ota): add partition-table signature handling for OTA updates

Implemented functionality to generate and compare partition-table
signatures during OTA updates. This enhancement ensures that the
target build's partition layout matches the device's actual layout,
improving the reliability of OTA updates and preventing issues
related to partition changes.

.github/workflows/build-observer-firmwares.yml

@@ -159,6 +159,8 @@ jobs:
         run: |
           mkdir -p out
           find artifacts -type f -name '*.bin' -exec cp -f {} out/ \;
+          # Per-env partition-table signatures (for the slim manifest's OTA gate).
+          find artifacts -type f -name '*.partsig' -exec cp -f {} out/ \;
           echo "Collected binaries:"; ls -1 out
 
       - name: Compute Short SHA
@@ -233,7 +235,8 @@ jobs:
             --config flasher/config.json \
             --out-dir flasher/v \
             --base-version "$FIRMWARE_VERSION" \
-            --build "$BUILD_NUMBER"
+            --build "$BUILD_NUMBER" \
+            --partsig-dir out
           printf '{\n  "baseVersion": "%s",\n  "build": %s\n}\n' \
             "$FIRMWARE_VERSION" "$BUILD_NUMBER" > flasher/observer-build-counter.json
           echo "Build $FIRMWARE_VERSION.$BUILD_NUMBER"