refactor: run module linters and collect code quality entries in the language processor (#15234)

This PR moves the linters' per-module bookkeeping out of the command
elaborator: the language processor now runs the module linters itself
and collects the linters' code quality entries per command from the
command snapshots. It also fixes the module linters' code quality
entries being dropped under `Elab.async`.

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Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>