test(cursor): cover dual composer key workspace routing

[ozymandiashh]

Summary

Follow-up to #599. The Cursor workspace map now reads both composer.composerData and composer.composerHeaders, but the regression coverage only exercised those keys in separate workspace DBs. This adds an end-to-end fixture where both rows exist in the same workspaceStorage/<hash>/state.vscdb and verifies the parser routes both composers into the real workspace source.

Without this case, a regression could still keep the workspace source visible via the legacy composer.composerData row while leaking composer.composerHeaders composers into the cursor orphan bucket.

What changed

• Refactored the Cursor workspace breakdown fixture helper so one workspace DB can contain multiple composer-list rows.
• Kept the legacy createWorkspaceDir(...) wrapper, so existing tests still write composer.composerData exactly as before.
• Added a parser-level regression test for a workspace containing both composer.composerData and composer.composerHeaders, including an orphan composer assertion to prove the headers composer does not fall through to cursor.

Testing

• npm test -- --run tests/providers/cursor.test.ts tests/providers/cursor-workspace-breakdown.test.ts -> 23 passed.
• npm run build -> succeeds.