feat(settings): reorganize the settings dialog and the model settings

Tabs Models, General, Drawing and About, each with a fixed title row.

The models tab becomes three pages: the user's providers with one status
each and the server's models; a searchable picker of all 24 providers in
four groups; and a provider page in three steps (connection, models,
test). A new provider gets its first suggested model, and a passing test
offers to use the model in the chat. Bedrock asks for one way of signing
in, with an optional session token for temporary access keys.

The composer's model picker lists every model, marking untested and
failed ones, and can open the provider picker. A chat error that offers
model settings opens the provider the request went to.

.github/workflows/test.yml

@@ -43,14 +43,8 @@ jobs:
         run: npm --prefix packages/mcp-server run build && npm --prefix packages/mcp-server run check-package
 
   e2e:
-    # Six jobs at once, each with a sixth of the tests and one worker: the
-    # same conditions per test, a fraction of the time
-    name: E2E Tests (${{ matrix.shard }}/6)
+    name: E2E Tests
     runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        shard: [1, 2, 3, 4, 5, 6]
     steps:
       - uses: actions/checkout@v6
 
@@ -82,7 +76,7 @@ jobs:
         run: npm run build
 
       - name: Run E2E tests
-        run: npm run test:e2e -- --shard=${{ matrix.shard }}/6
+        run: npm run test:e2e
         env:
           CI: true
 
@@ -90,6 +84,6 @@ jobs:
         uses: actions/upload-artifact@v6
         if: always()
         with:
-          name: playwright-report-${{ matrix.shard }}
+          name: playwright-report
           path: playwright-report/
           retention-days: 7