fix: rename embedded file_ops binary target to match external reference

The go_binary target in tools/file_ops/BUILD.bazel was still named
"file_ops_external" from the previous phase. This prevented the target
//tools/file_ops:file_ops from being found during the build.

Rename the target to "file_ops" to match all references in:
- toolchains/BUILD.bazel
- toolchains/file_ops_toolchain.bzl
- test/file_ops_integration/file_ops_test.bzl
- MODULE.bazel

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: avrabe

tools/file_ops/BUILD.bazel

@@ -21,7 +21,7 @@ wasm_precompile(
 
 # Wrapper binary that executes external WASM component with local AOT
 go_binary(
-    name = "file_ops_external",
+    name = "file_ops",
     srcs = ["main.go"],
     data = [
         ":file_ops_aot",  # Locally compiled AOT - guaranteed compatible!
@@ -33,13 +33,6 @@ go_binary(
     deps = ["@rules_go//go/runfiles"],
 )
 
-# Export for easy access in toolchains
-alias(
-    name = "file_ops_external_binary",
-    actual = ":file_ops_external",
-    visibility = ["//visibility:public"],
-)
-
 # Export WIT interface for toolchain use
 # This defines the file operations interface contract
 filegroup(