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-tray/src/linux.rs

@@ -51,7 +51,7 @@ impl ksni::Tray for HostTray {
     fn status(&self) -> ksni::Status {
         match &self.status {
             TrayStatus::Error(_) => ksni::Status::NeedsAttention,
-            s if s.pairing_attention() => ksni::Status::NeedsAttention,
+            s if s.pairing_attention() || s.has_conflicts() => ksni::Status::NeedsAttention,
             _ => ksni::Status::Active,
         }
     }