chore: consolidate parallel-session WIP (HOLD — do not push)

Local snapshot of intermingled in-flight work, committed to unblock the encode
refactor (a clean ffmpeg_win.rs for the vbv-dedup follow-on). These hunks span
the same files and can't be cleanly split here; the commit bundles three
distinct workstreams that each belong in their own PR:

  - logging rework (~43 files: level re-tiering, structured fields, `?e`,
    hot-path flood latches)
  - conflicting-host detection (detect.rs + detect/{linux,windows}.rs + wiring
    in main.rs/mgmt.rs/Cargo.toml/docs/packaging)
  - standby-sink DWM-stall attribution (windows/display_events.rs + capture/
    vdisplay wiring)

NOT verified as a combination. NOT to be pushed until the refactor is done and
these are re-verified and reorganized into their proper per-workstream PRs.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

crates/punktfunk-host/src/audio/linux/mod.rs

@@ -156,7 +156,10 @@ impl PwMicSource {
             .name("punktfunk-pw-mic".into())
             .spawn(move || {
                 if let Err(e) = mic_pw_thread(pcm_rx, quit_rx, channels, flush_t, ready_tx) {
-                    tracing::error!(error = %format!("{e:#}"), "pipewire virtual-mic thread failed");
+                    // Reaching here is always a setup/open failure (once the mainloop runs it exits
+                    // Ok) — and it was already reported to the pump via the ready handshake, which
+                    // owns the throttled operator-facing warn. Keep only a debug breadcrumb.
+                    tracing::debug!(error = %format!("{e:#}"), "pipewire virtual-mic setup failed — pump will back off and retry");
                 }
                 // Whether a clean quit or a daemon death: this instance is done — the pump reopens.
                 alive_t.store(false, Ordering::Release);
@@ -322,7 +325,7 @@ fn mic_pw_thread(
             .state_changed({
                 let mainloop = mainloop.clone();
                 move |_s, _ud, old, new| {
-                    tracing::info!(?old, ?new, "pipewire virtual-mic stream state");
+                    tracing::debug!(?old, ?new, "pipewire virtual-mic stream state");
                     // A stream error is unrecoverable for this instance — exit so the pump reopens.
                     if matches!(new, pw::stream::StreamState::Error(_)) {
                         mainloop.quit();
@@ -522,7 +525,7 @@ fn pw_thread(
     let _listener = stream
         .add_local_listener_with_user_data(tx)
         .state_changed(|_s, _ud, old, new| {
-            tracing::info!(?old, ?new, "pipewire audio stream state");
+            tracing::debug!(?old, ?new, "pipewire audio stream state");
         })
         .param_changed(|_stream, _tx, id, param| {
             let Some(param) = param else { return };

crates/punktfunk-host/src/audio/windows/wasapi_cap.rs

@@ -39,7 +39,7 @@ impl WasapiLoopbackCapturer {
             .name("punktfunk-wasapi-audio".into())
             .spawn(move || {
                 if let Err(e) = capture_thread(tx, stop_t, ready_tx, channels) {
-                    tracing::error!(error = format!("{e:#}"), "wasapi loopback thread failed");
+                    tracing::error!(error = %format!("{e:#}"), "wasapi loopback thread failed");
                 }
             })
             .context("spawn wasapi audio thread")?;