PLACEHOLDER_DEBUG_ID replacement

Trap: injecting the sourcemap debug ID but leaving PLACEHOLDER_DEBUG_ID in the JavaScript bundle looks sufficient because the debug comment and map are correct, but runtime registration still uses the dead UUID. Fix: replace the 36-character placeholder after injectDebugId(..., { skipSnippet: true }); equal UUID lengths preserve sourcemap positions. Verify the JS comment, debug_id, and debugId match and the placeholder is absent.