Remove globals.Buildarch from codebase (#31)

Remove the `Buildarch` field from the globals package and all references throughout the codebase.

**Changes:**
- Removed `Buildarch` package-level var and struct field from `internal/globals/globals.go`
- Removed `Buildarch` from the `New()` constructor
- Removed `globals.Buildarch = runtime.GOARCH` and unused `runtime` import from `cmd/webhooker/main.go`
- Removed `buildarch` from logger startup output in `internal/logger/logger.go`
- Removed all `Buildarch` test setup and assertions from globals, logger, database, and webhook_db_manager tests

All tests pass, `make check` passes, `docker build .` succeeds.

closes [issue #30](#30)

<!-- session: agent:sdlc-manager:subagent:5cae6803-6bdf-467d-9a56-43f135521e5f -->

Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Reviewed-on: #31
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>

internal/logger/logger.go

@@ -82,7 +82,6 @@ func (l *Logger) Identify() {
 	l.logger.Info("starting",
 		"appname", l.params.Globals.Appname,
 		"version", l.params.Globals.Version,
-		"buildarch", l.params.Globals.Buildarch,
 	)
 }
 

internal/logger/logger_test.go

@@ -11,7 +11,6 @@ func TestNew(t *testing.T) {
 	// Set up globals
 	globals.Appname = "test-app"
 	globals.Version = "1.0.0"
-	globals.Buildarch = "test-arch"
 
 	lc := fxtest.NewLifecycle(t)
 	g, err := globals.New(lc)
@@ -40,7 +39,6 @@ func TestEnableDebugLogging(t *testing.T) {
 	// Set up globals
 	globals.Appname = "test-app"
 	globals.Version = "1.0.0"
-	globals.Buildarch = "test-arch"
 
 	lc := fxtest.NewLifecycle(t)
 	g, err := globals.New(lc)