Type UAV public exports and launch helpers

[ethayu]

Refs #202.
Fixes #204.
Fixes #206.
Fixes #222.
Part of #201.

Summary

• Export top-level UAV/runtime symbols expected by type checkers.
• Type PX4 custom mode values.
• Type UAV launch and setup helper entry points.
• Folded Type PX4 custom mode values #203 and Type UAV launch helpers #223 into this PR as separate commits to reduce PR noise.

Verification

• Constituent focused Pyright, compile, ruff, and pytest checks from Type PX4 custom mode values #203, Type UAV public exports and launch helpers #205, and Type UAV launch helpers #223 passed when created.
• Integrated workspace Pyright baseline after condensation: 161 files analyzed, 0 errors, 0 warnings.