chore: untrack thoughts/ (planning docs) — already in .gitignore

thoughts/ contains planning docs, audit notes, state records, migration
plans — all local-only artefacts. It was already listed in .gitignore
(lines 220-221) but 47 files got committed before the gitignore entry
landed, so they kept being tracked.

git rm --cached keeps every file on disk; only the git index is updated.
This shrinks the PR diff to the actual code changes.

Made-with: Cursor

Author: sanchitmonga22