Move the frontend-agnostic pure functions and enums out of the Tauri
qconnect adapter into the shared crates, with zero behavior change. The
Tauri side keeps thin re-exports so all existing call sites compile
unchanged.
Into qconnect-app (new `session` module):
- should_arm_renderer_watchdog
- compute_connection_state + ServerActiveState + ConnectionDecision
- deferred_join_reason, should_reask_queue_state
- RendererStatus + from_wire
- quality_from_max_audio_quality
- QCONNECT_RENDERER_LOST_TIMEOUT_MS + JoinSession reason consts
Into qconnect-core (next to evaluate_remote_queue_admission):
- validate_track_origins_for_admission (pure over TrackOrigin); the
Tauri command wrapper stays thin and only maps wire origins to core
origins.
The 6 pure-fn unit tests move into the destination crates' test
modules. R5 honored: compute_connection_state matrix cells are relocated
verbatim, not changed.
cc