feat(lang): add Rust and TypeScript analyzer support

.github/workflows/ci.yml

@@ -21,6 +21,41 @@
           go-version: '1.26.1'
           cache: true
 
+      # Rust toolchain is required by the mutation-flavored Rust evals
+      # (cargo test is how survived-vs-killed is decided). Without this
+      # step, the mutation evals t.Skip via exec.LookPath("cargo").
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: stable
+          components: clippy
+
+      - name: Cache cargo registry + git + target
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            internal/lang/rustanalyzer/evaldata/**/target
+            cmd/diffguard/testdata/mixed-repo/**/target
+          key: cargo-${{ runner.os }}-${{ hashFiles('**/Cargo.toml', '**/Cargo.lock') }}
+          restore-keys: |
+            cargo-${{ runner.os }}-
+
+      # Node is required by the TS mutation evals (npm test -> vitest /
+      # node). Minimum 22.6 so `--experimental-strip-types` is default.
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+
+      - name: Cache npm
+        uses: actions/cache@v4
+        with:
+          path: ~/.npm
+          key: npm-${{ runner.os }}-${{ hashFiles('**/package.json', '**/package-lock.json') }}
+          restore-keys: |
+            npm-${{ runner.os }}-
+
       - name: Build
         run: go build ./...
 
@@ -30,6 +65,27 @@
       - name: Vet
         run: go vet ./...
 
+      # Dedicated eval passes. These are redundant with `go test ./...`
+      # above (which runs the same tests when cargo/node are present) but
+      # we run them separately so a failed eval is attributed to the
+      # right language subsystem in the CI log.
+      - name: Eval — Rust (EVAL-2)
+        env:
+          CI: "true"
+          CARGO_INCREMENTAL: "0"
+        run: make eval-rust
+
+      - name: Eval — TypeScript (EVAL-3)
+        env:
+          CI: "true"
+        run: make eval-ts
+
+      - name: Eval — Mixed / cross-cutting (EVAL-4 + E1)
+        env:
+          CI: "true"
+          CARGO_INCREMENTAL: "0"
+        run: make eval-mixed
+
   diffguard:
     # Dogfooding: run diffguard's own quality gate against this repo.
     # Mutation testing runs at 20% sample rate here as a fast smoke