feat: coordinate persistent detector collections

[DonLakeFlyer]

Adopts the persistent-collection tunnel protocol (TagTrackerTunnelProtocol f31024e7) for Python-mode rotations. The uavrt (C++ detector) path is unaffected except for the protocol-version gate noted below.

Protocol

• Replace START/STOP_ROTATION_DETECTION with START_COLLECTION, START_COLLECTION_SLICE and FINISH_COLLECTION, keyed by a per-rotation collection_id
• Handle COLLECTION_STATUS and gate slice completion on it instead of counting detector pulses
• Drop pulses and bearing results whose collection_id does not match the active rotation
• Track the controller protocol_version from its heartbeat; expose protocolCompatible / controllerProtocolVersion to QML

Behaviour change affecting both detection modes

SendTunnelCommandState now refuses to send any tunnel command until a compatible controller heartbeat has been received (and errors the state machine with a clear message otherwise). A controller without protocol_version in its heartbeat, or with a different version, is unusable with this build by design.

State machine

• SendTunnelCommandState takes an ackTimeoutMs parameter (default 2 s). StartCollection passes 35 s because the controller blocks up to 30 s waiting for detectors before acking — tracked in START_COLLECTION blocks up to 30 s before ACK; report detector startup progress to QGC instead MavlinkTagController2#118, which proposes async progress reporting instead
• Stop handler sends FINISH_COLLECTION cancel for the active collection

Build

• TunnelProtocol CPM pin bumped to f31024e7

Notes

• Pre-commit clang-format / clang-tidy / vehicle-null-check failures on these files are pre-existing across custom/ (baseline CustomPlugin.cc has 364 clang-format diffs; all 3 null-check hits are on untouched lines). Not reformatting unrelated code here.
• No automated tests for the protocol-compat gate; custom/ has no C++ unit-test infrastructure yet.