v0.1.2 - USB recovery and activity-gated acquisition

Adds bounded USB reset/reconnect after malformed capture framing or serial I/O failure, and negotiated activity-gated MON acquisition to avoid transferring quiet measurements. Predicted bursts and every 32nd acquisition scan use unfiltered CAP as a weak-signal backstop. Also explicitly selects the normal ESP32 LO divider and reports reset reason.

Validation: 18 local host/dashboard tests passed; GitHub Actions host tests and ESP32 build passed. A 65.16-second early monitor test achieved 94.39% capture-window coverage, with 410 quiet replies and no accepted packet. Window coverage is not continuous I/Q coverage.

A later standard-dashboard run on this revision, without changing the board placement, acquired four new validated 14AB packets between 23:04:29 and 23:05:49 America/New_York (2026-11-02). Latest: 17.8 C / 64.04 F and 89% RH. One intervening scheduled burst did not decode; reception remains intermittent. The 723-window session count includes hundreds of quiet acquisition scans, not 723 sensor transmissions.

The RF/harmonic interpretation remains unverified; this is not proof of direct 915 MHz reception or guaranteed range. See docs/API.md and docs/VALIDATION.md for protocol and measurement limits.