feat(compiler): Add grpc support for Swift

.agents/languages/swift.md

@@ -9,6 +9,7 @@ Load this file when changing `swift/` or Swift xlang behavior.
 - Swift code must compile without compiler warnings. Treat warnings as blockers, including warnings in generated Swift code.
 - Swift lint uses `swift/.swiftlint.yml`.
 - 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.

compiler/fory_compiler/cli.py

@@ -32,6 +32,7 @@
 from fory_compiler.generators.base import GeneratorOptions
 from fory_compiler.generators import GENERATORS
 from fory_compiler.generators.csharp import validate_csharp_generation
+from fory_compiler.generators.swift import validate_swift_generation
 from fory_compiler.generators.kotlin import (
     kotlin_output_paths,
     kotlin_package_for_schema,
@@ -342,6 +343,27 @@ def validate_csharp_files(
         return False
 
 
+def validate_swift_files(
+    files: List[Path],
+    import_paths: List[Path],
+    namespace_style: Optional[str] = None,
+    grpc: bool = False,
+) -> bool:
+    """Preflight Swift output paths and top-level symbols before writing output."""
+    cache: Dict[Path, Schema] = {}
+    graph: List[Tuple[Path, Schema]] = []
+    for file_path in files:
+        file_graph = collect_schema_graph(file_path, import_paths, cache, set())
+        if file_graph is None:
+            return False
+        graph.extend(file_graph)
+    try:
+        return validate_swift_generation(graph, namespace_style, grpc=grpc)
+    except ValueError as e:
+        print(f"Error: {e}", file=sys.stderr)
+        return False
+
+
 def validate_scala_import_packages(graph: List[Tuple[Path, Schema]]) -> bool:
     """Check package combinations that Scala source cannot compile."""
     packages = {scala_package_for_schema(schema) for _, schema in graph}
@@ -1022,6 +1044,11 @@ def cmd_compile(args: argparse.Namespace) -> int:
     if "scala" in lang_output_dirs:
         if not validate_scala_generation(args.files, import_paths, grpc=args.grpc):
             return 1
+    if "swift" in lang_output_dirs:
+        if not validate_swift_files(
+            args.files, import_paths, args.swift_namespace_style, grpc=args.grpc
+        ):
+            return 1
 
     if args.grpc_web and "javascript" not in lang_output_dirs:
         print(