Sample data collection

[LC-Linkous]

Summary

Hardening and verification pass across the whole library: process lifecycle,
cross-platform support, CLI/API surface, and docs. Everything below is
hardware-verified on Windows and Linux (full suite incl. hardware tests:
227/227 Linux on Debian 12, 228/228 Windows after the final fix, same bytes).

Behavior changes

• sweep() edges now snap outward to whole MHz (floor low / ceil high) —
  the swept range always contains the requested band
• monitor_frequencies() reads the bin covering each frequency (not a
  segment mean) and emits one complete update per sweep pass
• detect() reports the tool's own words (and versions) when no board is
  present, regardless of exit code

Fixed

• Abandoned streams could leave a child frozen in write() holding the USB
  claim for the rest of the process (found by the Linux hardware run)
• Device-busy open race absorbed with bounded retries in every mode
• Handle-mode output now drains live (read1); stop() escalation reaps

Added

• OS dead-man (Linux pdeathsig / Windows Job Object): a hard-killed parent
  cannot orphan a transmitter — proven with real parent SIGKILL tests
• Clean-interrupt tests with no Windows skips; CTRL_BREAK path proven
• CLI catch-up: tx --cw (duration-mandatory), monitor, scan,
  sweep -o/-B/-I
• Docstrings on the full public API, gated by test; SigMF sidecars validated
  with the official package
• Coverage gate 85%; CI matrix = hardware-verified platforms (Linux
  re-entered after verification)

Housekeeping

• LF everywhere via .gitattributes (one renormalize commit); binary/fixture
  protections
• SETUP_LINUX.md merged into the README; docs refreshed repo-wide;
  regenerable fm_testdata untracked

Version stays 1.0.0 — the 1.1.0 roll (changelog consolidation, bump, tag)
follows as its own change.