ci: stop rewriting flasher config.json; sync release notes to the release body

The flasher's versions become feed-driven (/releases on the firmware
proxy Worker): config.json's observer entries turn into github release
defs with no embedded filenames, so update-firmware.py would find zero
matches and exit nonzero — remove the call before the config conversion
lands. Changelog notes now ride the release body via a non-fatal
'gh release edit --notes-file firmware-notes.html' in the publish step.

MUST land before the flasher config.json conversion, or the next build
goes red at Update Flasher Config.

Workflow-only commit: pushing this triggers no build.

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

@@ -189,6 +189,13 @@ jobs:
           # not published as release assets (and they'd break the hash-based prune).
           gh release upload "$RELEASE_TAG" $(find out -maxdepth 1 -type f ! -name '*.partsig') --clobber
 
+          # Keep the release body in sync with the repo's notes source: the
+          # /releases feed serves it as the flasher dropdown's changelog
+          # (config.json no longer carries per-version notes). Non-fatal —
+          # stale notes beat a red build whose binaries are already live.
+          gh release edit "$RELEASE_TAG" --notes-file firmware-notes.html \
+            || echo "WARNING: release notes sync failed" >&2
+
           # Prune old assets, but RETAIN the most recent KEEP_BUILDS build hashes
           # (not just the current one). The flasher SPA reads config.json once at
           # page load and the embedded git short-hash is what links it to assets;
@@ -226,11 +233,10 @@ jobs:
           token: ${{ secrets.FLASHER_DISPATCH_TOKEN }}
           path: flasher
 
-      - name: Update Flasher Config
-        run: |
-          python3 flasher/scripts/update-firmware.py \
-            "${{ steps.sha.outputs.short }}" \
-            "$GITHUB_WORKSPACE/firmware-notes.html"
+      # update-firmware.py is no longer called here: config.json's observer
+      # entries are github release defs (no embedded filenames to rewrite), the
+      # flasher's versions come from the Worker's /releases feed, and the
+      # changelog notes ride the release body (see the publish step).
 
       - name: Generate Slim Per-Variant Manifests + Persist Build Counter
         env:
@@ -289,9 +295,9 @@ jobs:
       - name: Commit & Push Flasher Config
         working-directory: flasher
         run: |
-          # Stage everything: update-firmware.py edits config.json in place, but the
-          # slim manifests (v/*.json) and the build counter can be NEW files, which
-          # `commit -am` would miss — so add -A and check the staged diff.
+          # Stage everything: the slim manifests (v/*.json) and the build counter
+          # can be NEW files, which `commit -am` would miss — so add -A and check
+          # the staged diff. (config.json is no longer rewritten per build.)
           git add -A
           if git diff --cached --quiet; then
             echo "No flasher changes to commit."