T2: CI runs every test against a throwaway mongod

tools/ci/with-test-mongod.sh starts mongod (or podman's mongo:8) on a random localhost port
with a temporary data directory, runs the command, and removes both. build.yml and deploy.yml
test through it, so the ~85 integration tests stop being skipped in CI. MongoFixture refuses
production's port and data directory, and in CI anything but the wrapper's mongod; with
PRIVAPUB_TEST_REQUIRE_MONGOD=1 a missing mongod fails instead of skipping.

The deploy now passes the PRIVAPUB_SMOKE_TOKEN secret to the Mastodon smoke check, so its
signed-in half runs once the owner creates the persona and the secret.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ELjqpznMFMNrJoJUj6K5p2

.gitea/workflows/build.yml

@@ -15,5 +15,5 @@ jobs:
       - name: Build
         run: dotnet build PrivaPub.sln -c Release
 
-      - name: Test
-        run: dotnet test PrivaPub.sln -c Release --no-build
+      - name: Test (unit and integration, on a throwaway mongod)
+        run: tools/ci/with-test-mongod.sh dotnet test PrivaPub.sln -c Release --no-build