feat: Cross-Language SDK — Phases 2-4 + gRPC debt fix + dogfooding

TypeScript/Napi-RS bindings (Phase 2):
- 4 kernel classes: AmplifierSession, Coordinator, HookRegistry, CancellationToken
- JsToolBridge for TypeScript module authoring
- 64 Vitest tests, CI split into separate node-tests job

gRPC Phase 2 debt fix:
- 5 proto optional fields, full bidirectional conversions
- All 9 KernelService RPCs implemented (was 1 of 9)
- Session holds Arc<Coordinator> with coordinator_shared()

WASM module loading (Phase 3):
- 6 WASM bridges via Component Model (Tool, Hook, Context, Approval, Provider, Orchestrator)
- amplifier-guest crate with export macros
- WIT interface definitions for all 6 module types
- 6 test fixture .wasm binaries

Cross-language module resolver (Phase 4):
- Auto-detect transport: .wasm → WASM, amplifier.toml → gRPC, __init__.py → Python
- WASM component metadata parsing for module type detection
- PyO3 + Napi-RS bindings for resolver
- loader_dispatch.py wired to Rust

Dogfooding:
- _session_init.py routes through loader_dispatch
- Mixed-transport E2E: native + WASM modules in same session
- Python and TypeScript WASM session examples

Security fixes:
- pyo3 0.28.1 → 0.28.2 (HIGH severity)
- wasmtime 29 → 42 (8 alerts cleared)

🤖 Generated with Amplifier

Co-Authored-By: Amplifier <240397093+microsoft-amplifier@users.noreply.github.com>

Author: bkrabach

.github/workflows/rust-core-ci.yml

@@ -19,11 +19,32 @@ jobs:
       - name: Run Rust tests
         run: cargo test -p amplifier-core --verbose
       - name: Check workspace
-        run: cargo check --workspace
+        run: cargo check -p amplifier-core -p amplifier-core-py
       - name: Rustfmt
-        run: cargo fmt --check
+        run: cargo fmt -p amplifier-core -p amplifier-core-py --check
       - name: Clippy
-        run: cargo clippy --workspace -- -D warnings
+        run: cargo clippy -p amplifier-core -p amplifier-core-py -- -D warnings
+
+  node-tests:
+    name: Node.js Binding Tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+      - name: Build native module
+        working-directory: bindings/node
+        run: |
+          npm install
+          npm run build
+      - name: Run tests
+        working-directory: bindings/node
+        run: npx vitest run
+      - name: Clippy (Node binding)
+        run: cargo clippy -p amplifier-core-node -- -D warnings
 
   python-tests:
     name: Python Tests (${{ matrix.python-version }})