conftest: lazy-load imports to speed up pytest collection

[AgentsLogic]

Fixes #32611

Summary

This PR speeds up pytest collection by:

1. Lazy-loading expensive imports in conftest.py - Moves OpenpilotPrefix, manager, TICI, and HARDWARE imports from module-level to inside the fixtures where they're actually used. These imports are only needed when tests run, not during collection.

2. Replacing TICI import with file check - Instead of importing the entire openpilot.system.hardware module just to check TICI, uses a simple os.path.isfile('/TICI') check which is much faster.

3. Using norecursedirs instead of --ignore flags - The norecursedirs option is more efficient for pytest collection as it prevents pytest from even entering those directories, rather than ignoring them after discovery.

Changes

• conftest.py: Move imports inside fixtures, add _is_tici() helper function
• pyproject.toml: Replace --ignore flags with norecursedirs configuration

[AgentsLogic]

ready for review