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>

packaging/debian/build-deb.sh

@@ -210,6 +210,14 @@ if [ "$1" = "configure" ]; then
         echo "    sudo firewall-cmd --permanent --add-service=punktfunk-native && sudo firewall-cmd --reload"
         echo "    (use punktfunk-gamestream for the Moonlight-compat host)"
     fi
+    # Conflicting Moonlight-compatible host (Sunshine/Apollo/...): reuse the host's own detector so
+    # the warning lives in one place. Exit 1 = found; never fail the install on it.
+    if command -v punktfunk-host >/dev/null 2>&1; then
+        if ! conflict="$(punktfunk-host detect-conflicts 2>/dev/null)"; then
+            echo ""
+            echo "$conflict"
+        fi
+    fi
 fi
 exit 0
 EOF