Make the Chrome Web Store ID the single canonical extension ID

The extension is now published (ID: mkiffclapimhbjjlgkndlillglopbcic).
Drop the pinned "key" field from manifest.json (the Store rejects it
anyway) and use the Store-assigned ID everywhere instead of juggling
two IDs: native-host/com.kget_capture.host.json's allowed_origins,
keys/extension-id.txt, and docs. This also removes the need for a
separate key-stripped release zip, since there's no key left to strip.

.github/workflows/release.yml

@@ -18,34 +18,14 @@ jobs:
       - name: Package extension
         # Chrome requires manifest.json at the zip root, both for Web Store
         # upload and for manually loading unpacked -- so this one archives
-        # only extension/'s contents, not the whole repo. Keeps the pinned
-        # "key" field, so unpacked loads get the stable, predictable ID.
+        # only extension/'s contents, not the whole repo. No "key" field to
+        # worry about: the Web Store's own assigned ID is now the single
+        # canonical one (see keys/README.md), so this same zip works for
+        # both a Store upload and a manual unpacked install.
         run: |
           cd extension
           zip -r "../kget-capture-extension-${GITHUB_REF_NAME}.zip" .
 
-      - name: Package extension for Web Store upload
-        # The Chrome Web Store dashboard rejects any manifest containing a
-        # "key" field ("key field is not allowed in manifest") -- it assigns
-        # its own permanent ID on first publish instead. Strip it from a
-        # copy so this zip is upload-ready; the other extension zip above
-        # keeps "key" for stable unpacked/dev IDs.
-        run: |
-          rm -rf /tmp/store-extension
-          cp -r extension /tmp/store-extension
-          python3 -c "
-          import json
-          path = '/tmp/store-extension/manifest.json'
-          with open(path) as f:
-              manifest = json.load(f)
-          manifest.pop('key', None)
-          with open(path, 'w') as f:
-              json.dump(manifest, f, indent=2)
-              f.write('\n')
-          "
-          cd /tmp/store-extension
-          zip -r "$OLDPWD/kget-capture-store-${GITHUB_REF_NAME}.zip" .
-
       - name: Package source
         # Separately, the native-host installer bundle (install.sh,
         # native-host/, keys/) needs the whole repo. git archive only
@@ -59,5 +39,4 @@ jobs:
           files: |
             kget-capture-${{ github.ref_name }}.zip
             kget-capture-extension-${{ github.ref_name }}.zip
-            kget-capture-store-${{ github.ref_name }}.zip
           generate_release_notes: true