ci: add workspace clippy + test gate workflow

Until now no CI workflow ran the test suite or clippy at all — the
android-release, docker-build, web-e2e, web-wasm-rebuild, and
builder-image workflows cover packaging and e2e, but a direct push to
master (including the web-wasm-rebuild bot commit) never executed
cargo test or clippy. The gate discipline in CLAUDE.md §6 existed only
on developer machines.

test.yml runs the exact §6 commands (clippy --workspace --all-targets
-D warnings; cargo test --workspace) on master pushes and PRs, with
SQLX_OFFLINE against the checked-in .sqlx cache, path-filtered so
docs-only merges don't burn CI. Toolchain/cache mirror web-e2e.yml.

Found during the 2026-07-06 large-scale review (finding H1).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitea/workflows/test.yml

@@ -0,0 +1,56 @@
+# Workspace gate: the same clippy + test commands CLAUDE.md §6 requires
+# locally, run on every master push and pull request. Until this workflow
+# existed, nothing in CI ran the test suite at all — a direct push to
+# master (or the web-wasm-rebuild bot commit) was entirely unguarded.
+name: Test
+
+on:
+  push:
+    branches: [master]
+    paths:
+      - 'solitaire_app/**'
+      - 'solitaire_assetgen/**'
+      - 'solitaire_core/**'
+      - 'solitaire_data/**'
+      - 'solitaire_engine/**'
+      - 'solitaire_server/src/**'
+      - 'solitaire_server/tests/**'
+      - 'solitaire_server/migrations/**'
+      - 'solitaire_sync/**'
+      - 'solitaire_wasm/**'
+      - 'solitaire_web/**'
+      - 'Cargo.toml'
+      - 'Cargo.lock'
+      - '.cargo/**'
+      - '.sqlx/**'
+      - '.gitea/workflows/test.yml'
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          components: clippy
+
+      - name: Cache cargo build
+        uses: Swatinem/rust-cache@v2
+
+      # SQLX_OFFLINE uses the checked-in `.sqlx/` query cache (no live DB),
+      # same as the web-e2e workflow's server prebuild.
+      - name: Clippy (deny warnings)
+        env:
+          SQLX_OFFLINE: 'true'
+        run: cargo clippy --workspace --all-targets -- -D warnings
+
+      - name: Test
+        env:
+          SQLX_OFFLINE: 'true'
+        run: cargo test --workspace