fix: replace copyleft input dependencies

[abrichr]

Summary

• restores the default Recorder runtime/import contract from fix: restore capture runtime contract #39
• removes pynput and oa-atomacos from the shipped runtime and archive metadata
• replaces global input capture with native, fail-loud observers:
  • macOS: listen-only Quartz event tap with explicit Input Monitoring checks
  • Windows: low-level hooks with a bounded raw queue and off-hook layout translation
  • Linux/X11: XInput2 with state-aware XKB/libxkbcommon text handling
• keeps hook/event callbacks nonblocking through bounded delivery queues
• preserves OS receipt timestamps and keyboard/mouse ordering through one Recorder observer
• treats ambiguous dead/compose text as unverifiable unless locale compose state commits exact text
• preserves auxiliary mouse buttons through storage and event processing
• surfaces startup, runtime, queue-overflow, permission, teardown, and Recorder worker failures to the caller

Release boundary

pynput remains only in the local development dependency group as a synthetic-input test driver. It is absent from:

• project runtime dependencies
• wheel and sdist Requires-Dist
• packaged openadapt_capture source

The distribution verifier now rejects both pynput and oa-atomacos if either re-enters a release archive.

Verification

• 265 passed, 7 skipped — full macOS/unit suite excluding the separately scoped browser-bridge test
• 138 passed, 1 skipped — focused native observer, Recorder, runtime-import, and window contracts
• ruff check openadapt_capture/
• git diff --check
• clean wheel and sdist built from the exact PR head
• both archives passed scripts/verify_distribution.py
• wheel contents confirmed all four native observer modules and no forbidden runtime dependency

This is the consolidated replacement for #39. #39 should not merge separately.