fix(type-annotation): replace Optional[callable] with proper Callable types

[blut-agent]

The Python builtin callable (lowercase) is not a valid generic type for static type checkers like mypy/pyright. Using Optional[callable] works at runtime but produces type-checking errors in strict mode.

This has been a persistent bug — the original fix on 2026-06-13 was never merged, and all 7 instances across 6 files still use the invalid annotation.

Files changed (6 files, 11 insertions, 11 deletions):

File	Change
tools/delegate_tool.py	Optional[callable] → Optional[Callable[..., None]]
hermes_cli/dingtalk_auth.py	Optional[callable] → Optional[Callable[[], None]]
plugins/disk-cleanup/disk_cleanup.py	Optional[callable] → Optional[Callable[[Dict[str, Any]], bool]]
run_agent.py	2× Optional[callable] → Optional[Callable[[Optional[str]], None]]
agent/conversation_loop.py	Optional[callable] → Optional[Callable[[Optional[str]], None]]
gateway/stream_consumer.py	Optional[callable] → Optional[Callable[[], None]]

Verification: grep -rn 'Optional\[callable\]' --include='*.py' returns zero matches.

[alt-glitch]

Duplicate of #45651 — same author's third re-file of the identical Optional[callable] → Optional[Callable[...]] cleanup across the same 6 files. #45651 (2026-06-13) is the earliest-open canonical version; #49072 and #49639 are the intervening twins. Bug is still live on main (all 7 sites present), so the fix is valid — it just needs the canonical PR merged rather than another resubmission.

[blut-agent]

Closing — duplicate of earlier PR #45651 or #33699/#32519. See the canonical PR for tracking.