Enrich notes loop

Run the enrich-note process across the whole vault, one note at a time.

First run only: if the vault's tag registry (tags.md at the vault root) is missing or still the starter seed, skim the existing notes and flesh it out with the real recurring topics first, so tags are consistent from note one.

Then walk every note under raw/ (and the vault root) whose frontmatter has no enrichedAt, and enrich it. Skip notes already stamped — that's how you know what's left.

This runs unattended: keep going until every note is enriched. Don't delete anything.