chore: remove dead pass statement in db.py TYPE_CHECKING block

[cyrusagent]

Assignee: jeremy

Summary

Removes a dead pass statement inside the if TYPE_CHECKING: block in src/kb/db.py. The block already imports Path, so the pass is unreachable and was leftover from a refactor.

 if TYPE_CHECKING:
     from pathlib import Path

-    pass
-
 EMBEDDING_DIM = 1024

Why

Pure no-op cleanup — the pass is dead code (a TYPE_CHECKING block with at least one import doesn't need it). No behavior change, no test changes.

Linear

Closes TEN-1 — "Find a small improvement".

Test plan

• File parses (python3 -c "import ast; ast.parse(...)")
• CI runs ruff + mypy + pytest on the diff (no logic changed, expected to pass)

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