weft-check

Run the compiler over this project and fix what it names, without running anything. 1. Read the `weft-language` skill if you have not this session, and the `metadata.json` of any node type you are about to edit. Then: `weft validate --file src/main.weft < src/main.weft`. 2. Parse the diagnostics. Errors are `line:column message` with a stable slug; the message names the fix. Fix every Error, then re-validate until the list is empty. Never route around a diagnostic, and never weaken the program to silence one: if a fix feels wrong, stop and say what the compiler is asking for instead. A `level-too-large` warning is not an error, but answer it the same way: [the level rule] is a law, and the fix is a group, never a wider level. 3. Then `weft build`. If it fails, read the error, fix, rebuild. 4. Report, in plain words: what was wrong, what you changed, and the current state (clean validate, clean build). No summary of the diff.