ci(web): build wasm in the deploy pipeline instead of committing it (#156)

The wasm bundles in solitaire_server/web/pkg/ are no longer tracked. The
web-wasm-rebuild workflow (which rebuilt them in CI and committed them
back to master) is gone; instead:

- solitaire_server/Dockerfile gains a wasm-builder stage that runs
  build_wasm.sh with the same pinned toolchain (wasm-bindgen 0.2.120,
  wasm-pack 0.14.0, binaryen 130) and the runtime image copies pkg/
  from it — the image build is now the artifacts' single source of truth.
- web-e2e builds the wasm before Playwright runs, and its trigger paths
  now include the wasm-feeding crates it actually tests.
- docker-build triggers on solitaire_data/** and build_wasm.sh too, so
  every wasm-affecting change redeploys.
- Self-hosters serving /web or /play from a source checkout run
  ./build_wasm.sh once (script header and ARCHITECTURE.md updated).

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

.gitea/workflows/web-e2e.yml

@@ -8,9 +8,13 @@ on:
       - 'solitaire_server/src/**'
       - 'solitaire_server/e2e/**'
       - 'solitaire_wasm/**'
+      - 'solitaire_web/**'
+      - 'solitaire_engine/**'
+      - 'solitaire_data/**'
       - 'solitaire_core/**'
       - 'Cargo.toml'
       - 'Cargo.lock'
+      - 'build_wasm.sh'
       - '.gitea/workflows/web-e2e.yml'
   workflow_dispatch:
 
@@ -24,10 +28,31 @@ jobs:
 
       - name: Install Rust
         uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: wasm32-unknown-unknown
 
       - name: Cache cargo build
         uses: Swatinem/rust-cache@v2
 
+      # The wasm bundles (solitaire_server/web/pkg/) are not in the repo —
+      # build them here so the served pages have real wasm to load. Tool
+      # versions are pinned; keep in sync with solitaire_server/Dockerfile.
+      - name: Install wasm-bindgen-cli + wasm-pack (pinned)
+        uses: taiki-e/install-action@v2
+        with:
+          tool: wasm-bindgen-cli@0.2.120,wasm-pack@0.14.0
+
+      - name: Install binaryen 130 (wasm-opt, pinned)
+        run: |
+          set -euo pipefail
+          curl -sSL \
+            https://github.com/WebAssembly/binaryen/releases/download/version_130/binaryen-version_130-x86_64-linux.tar.gz \
+            | tar xz
+          echo "$PWD/binaryen-version_130/bin" >> "$GITHUB_PATH"
+
+      - name: Build WASM artifacts
+        run: ./build_wasm.sh
+
       # Prebuild the server so Playwright's `webServer` (which runs
       # `cargo run -p solitaire_server`) starts from a compiled binary instead
       # of cold-compiling the whole dependency graph (axum/sqlx/reqwest) inside