feat(compiler): Add grpc support for Swift

.agents/languages/swift.md

@@ -13,6 +13,7 @@ Load this file when changing `swift/` or Swift xlang behavior.
 - Swift formatting uses `swift/.swift-format`; do not rely on SwiftLint for indentation or source
   formatting.
 - Use `ENABLE_FORY_DEBUG_OUTPUT=1` when debugging Swift tests.
+- Generated Swift gRPC companions are compiler-owned files targeting grpc-swift 1.x. Keep grpc-swift out of the `swift/` runtime package; it belongs only to generated user code and the compiler build fixture.
 - Prefer the user-requested or existing Foundation public value type when it is the intended Swift surface; do not invent Fory-prefixed wrappers only to avoid import ambiguity.
 - Preserve distinct temporal semantics. Timestamp values and day-only local dates should have protocol-accurate helper names and no stale aliases after a refactor.
 - When temporal or public-type refactors touch generated Swift code, sweep message fields, union payloads, macros, xlang harnesses, and integration fixtures together.

.github/workflows/ci.yml

@@ -1,3 +1,3 @@
 # Licensed to the Apache Software Foundation (ASF) under one
 # or more contributor license agreements.  See the NOTICE file
 # distributed with this work for additional information
@@ -1016,6 +1016,49 @@
           cd integration_tests/grpc_tests/java
           mvn -T16 --no-transfer-progress -Dtest=DartGrpcTest test
 
+  grpc_java_swift_tests:
+    name: Java/Swift gRPC Tests
+    needs: changes
+    if: needs.changes.outputs.grpc_tests == 'true' || needs.changes.outputs.swift == 'true'
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v5
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: 21
+          distribution: "temurin"
+      - name: Set up Python 3.11
+        uses: actions/setup-python@v5
+        with:
+          python-version: 3.11
+          cache: "pip"
+      - name: Cache Maven local repository
+        uses: actions/cache@v4
+        with:
+          path: ~/.m2/repository
+          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
+          restore-keys: |
+            ${{ runner.os }}-maven-
+      - name: Install Java artifacts for gRPC tests
+        run: |
+          cd java
+          mvn -T16 --no-transfer-progress clean install -DskipTests -Dmaven.javadoc.skip=true -Dmaven.source.skip=true
+      - name: Generate gRPC test sources
+        run: python integration_tests/grpc_tests/generate_grpc.py
+      - name: Build Swift gRPC peer
+        run: |
+          cd integration_tests/grpc_tests/swift/interop
+          swift build -c release --product interop
+      - name: Run Swift gRPC package tests
+        run: |
+          cd integration_tests/grpc_tests/swift/interop
+          swift test
+      - name: Run Java/Swift gRPC Tests
+        run: |
+          cd integration_tests/grpc_tests/java
+          mvn -T16 --no-transfer-progress -Dtest=SwiftGrpcTest test
+
   javascript:
     name: JavaScript CI
     needs: changes