fix: resolve TinyGo toolchain platform resolution issue

Add platform transitions to Go component rules for proper WebAssembly targeting:

• Import wasm_transition from rust:transitions.bzl in go/defs.bzl
• Apply cfg = wasm_transition to go_wasm_component rule
• Apply cfg = wasm_transition to go_wasm_component_wizer rule
• Apply cfg = wasm_transition to go_wit_bindgen rule

This resolves the toolchain resolution failure where Go components were
trying to build for host platform instead of WebAssembly target platform.

The TinyGo toolchain now properly resolves and builds Go components:
- TinyGo v0.38.0 with WASI Preview 2 support
- WebAssembly component generation via wasm-tools
- Full integration with existing platform constraint system

Tested and verified working with go_component examples.

Author: avrabe

go/defs.bzl

@@ -28,6 +28,7 @@ Example usage:
 """
 
 load("//providers:providers.bzl", "WasmComponentInfo")
+load("//rust:transitions.bzl", "wasm_transition")
 
 def _go_wasm_component_impl(ctx):
     """Implementation of go_wasm_component rule using TinyGo + WASI Preview 2"""
@@ -352,6 +353,7 @@ EOF
 # TinyGo WebAssembly Component rule
 go_wasm_component = rule(
     implementation = _go_wasm_component_impl,
+    cfg = wasm_transition,
     attrs = {
         "srcs": attr.label_list(
             allow_files = [".go"],
@@ -431,6 +433,7 @@ def _go_wit_bindgen_impl(ctx):
 # Standalone Go WIT bindings generation rule
 go_wit_bindgen = rule(
     implementation = _go_wit_bindgen_impl,
+    cfg = wasm_transition,
     attrs = {
         "wit": attr.label(
             allow_single_file = [".wit"],
@@ -602,6 +605,7 @@ def _go_wasm_component_wizer_impl(ctx):
 # TinyGo WebAssembly Component rule with Wizer pre-initialization
 go_wasm_component_wizer = rule(
     implementation = _go_wasm_component_wizer_impl,
+    cfg = wasm_transition,
     attrs = {
         "srcs": attr.label_list(
             allow_files = [".go"],