Fix envoy_proto_descriptor for Protobuf v29+ with bzlmod

- Update envoy_proto_descriptor macro to explicitly reference WKT proto files
- Add protobuf patch to export WKT proto files with public visibility
- Modify plugin.proto visibility to public for bzlmod compatibility

Co-authored-by: phlax <454682+phlax@users.noreply.github.com>

Author: Copilot

bazel/envoy_build_system.bzl

@@ -211,8 +211,21 @@ def envoy_proto_descriptor(name, out, srcs = [], external_deps = []):
         include_paths.append("external/com_google_googleapis")
 
     if "well_known_protos" in external_deps:
-        srcs.append("@com_google_protobuf//:well_known_type_protos")
-        srcs.append("@com_google_protobuf//:descriptor_proto_srcs")
+        # Explicitly reference Well Known Types from their correct packages
+        # to support Protobuf v29+ (bzlmod) structure.
+        # Reference the proto files directly from the subpackages where they are declared.
+        srcs.append("@com_google_protobuf//src/google/protobuf:any.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf:api.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf:descriptor.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf:duration.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf:empty.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf:field_mask.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf:source_context.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf:struct.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf:timestamp.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf:type.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf:wrappers.proto")
+        srcs.append("@com_google_protobuf//src/google/protobuf/compiler:plugin.proto")
         include_paths.append("external/com_google_protobuf/src")
 
     options = ["--include_imports"]

bazel/protobuf.patch

@@ -102,3 +102,48 @@ index e9ced612f..9454a47bd 100755
 +        __import__('pkg_resources').declare_namespace(__name__)
 +    except ImportError:
 +        __path__ = __import__('pkgutil').extend_path(__path__, __name__)
+diff --git a/src/google/protobuf/BUILD.bazel b/src/google/protobuf/BUILD.bazel
+--- a/src/google/protobuf/BUILD.bazel
++++ b/src/google/protobuf/BUILD.bazel
+@@ -24,6 +24,25 @@ package(
+     ],
+ )
+ 
++# Export Well Known Type proto files for use by genrules and other build rules.
++# This is needed for bzlmod compatibility where file targets need to be explicitly exported.
++exports_files(
++    [
++        "any.proto",
++        "api.proto",
++        "descriptor.proto",
++        "duration.proto",
++        "empty.proto",
++        "field_mask.proto",
++        "source_context.proto",
++        "struct.proto",
++        "timestamp.proto",
++        "type.proto",
++        "wrappers.proto",
++    ],
++    visibility = ["//visibility:public"],
++)
++
+ proto_library(
+     name = "any_proto",
+     srcs = ["any.proto"],
+diff --git a/src/google/protobuf/compiler/BUILD.bazel b/src/google/protobuf/compiler/BUILD.bazel
+--- a/src/google/protobuf/compiler/BUILD.bazel
++++ b/src/google/protobuf/compiler/BUILD.bazel
+@@ -344,11 +344,7 @@ filegroup(
+ 
+ exports_files(
+     srcs = ["plugin.proto"],
+-    visibility = [
+-        "//:__pkg__",
+-        "//python:__pkg__",
+-        "//ruby:__pkg__",
+-    ],
++    visibility = ["//visibility:public"],
+ )
+ 
+ cc_library(