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/gamestream/mod.rs

@@ -218,6 +218,17 @@ pub fn serve(
         gamestream,
         "punktfunk host"
     );
+    // Surface a conflicting Moonlight-compatible host (Sunshine/Apollo/…) as early as possible:
+    // scan once (cached for `/local/summary` → tray + web console) and warn loudly if found.
+    let conflicts = crate::detect::init();
+    if !conflicts.is_empty() {
+        tracing::warn!(
+            target: "punktfunk::detect",
+            count = conflicts.len(),
+            "{}",
+            crate::detect::render_report(conflicts)
+        );
+    }
     if gamestream {
         tracing::warn!(
             "GameStream/Moonlight compat ENABLED (--gamestream): its pairing runs over plain HTTP and \