feat(venue): reactive crowd video layer behind the 3D highway (career mode 1/3) (#905)

* feat(venue): reactive crowd video layer behind the 3D highway (career mode PR1)

Two crossfading video backdrop planes in the highway_3d venue background
style, driven by a new venue-crowd.js state machine that maps
v3:live-performance-state to crowd states (bored/neutral/engaged/ecstatic)
with 3s stability + 8s dwell hysteresis, plus one-shot reaction stingers
on streak milestones and end-of-song accuracy. Inert without a venue pack
manifest (career plugin, PR2) or the feedBack-venue-crowd-dev flag — the
static bg plate behaves exactly as before.

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

* fix(venue-crowd): retry renderer binding + preserve mid-stinger transitions

Codex preflight P2s: (1) videos created before highway_3d registered its
globals never reached the backdrop planes — binding is now idempotent and
retried from start/perf-event/re-activation paths; (2) a crowd-state
switch committing while a stinger played was dropped because the machine
had already advanced — it is now deferred and played when the stinger ends.

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

* fix(venue-crowd): per-video load tokens + unbind renderer on stop

Codex preflight round 2: (1) the global load token let a stinger cancel a
committed loop load on the other layer — tokens are now per-element, and a
stinger preempting an in-flight loop on its own layer requeues that loop
for when the stinger ends; (2) setManifest(null)/deactivate left the last
crowd frame bound and visible over the static plate — stop() now unbinds
both layers from the renderer and zeroes the mix.

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

* fix(venue-crowd): flush deferred loop on stinger failure, source accuracy from perf events

Codex preflight round 3: (1) a failed/timed-out stinger left a deferred
loop switch queued forever; the failure path now flushes it. (2)
stats:recorded only carries {filename, arrangement}, so the end-of-song
reaction now uses the accuracyPct from the song's last
v3:live-performance-state event (a real percentage) instead of a field
that never existed.

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

* fix(venue-crowd): requeue mid-crossfade loops preempted by stingers; hard-stop on manifest swap

Codex preflight round 4: (1) idleLayer() still points at the fading-in
layer during a crossfade, so a stinger firing mid-fade overwrote the new
loop with nothing requeued — the fading loop is now tracked and requeued
like an in-flight load; (2) swapping venue packs while active now goes
through stop() so _stopGen invalidates the old manifest's in-flight loads.

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

* fix(venue-crowd): generation-gate stinger handlers; recrop on video size change

Codex preflight round 5: (1) an ended/timeout handler orphaned by stop()
could fire into a later stinger's lifecycle on the reused element — handlers
now detach unconditionally and carry a generation token; (2) the renderer
only re-applied cover-crop on camera aspect changes, so a src swap with a
different intrinsic size kept stale repeat/offset — it now recrops when
videoWidth/Height change.

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

* fix(venue-crowd): bail loop-fade completion when a stinger preempted the layer

Codex preflight round 6: the loop crossfade's completion callback could
still run between a stinger's start and its canplaythrough, promoting the
stinger's layer to active and pausing the real loop — it now bails when
the fading loop was preempted.

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

* fix(venue-crowd): keep rear video layer opaque during crossfades

Two half-transparent layers let the static bg plate bleed through (~25%
at mid-fade) — visible as a flash of the old still image on every state
transition. The crossfade is now always the front layer fading over an
opaque rear layer.

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

* fix(venue-crowd): reset active layer with mix on stop

Codex preflight: stop() zeroed the mix but left _activeLayer at 1, so a
restart flashed layer 0's stale frame until the new loop loaded.

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

* fix(venue-crowd): reset crowd mood to neutral on song load

Codex preflight: a song ending in ecstatic/bored left the next song's
crowd stuck in that mood until the hysteresis window passed.

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

* fix(venue-crowd): cancel in-flight fade when a stinger preempts it

Codex preflight: the orphaned ramp kept pushing the mix toward the layer
whose src the stinger had just replaced.

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

* fix(venue-crowd): don't let null accuracy resets wipe the end-of-song value

Codex preflight: Number(null) is 0, so idle HUD resets overwrote
_lastAccuracyPct before stats:recorded consumed it, suppressing the
end-of-song stinger.

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

* fix(venue-crowd): abort stale stinger state on song load

Codex preflight: a stinger straddling a song change could fade back into
the previous song's layer or flush its pending loop.

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

* fix(venue-crowd): always detach load listeners, gate only the callback

Codex preflight: superseded loads left canplaythrough/error listeners
attached to the persistent video elements — unbounded growth over a
session.

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

* feat(venue-crowd): flyover intro with crowd-ambience ducking

On song:loaded, an optional pack intro plays once: a camera flyover video
(idle layer, one-shot) with bar-crowd ambience audio that ducks out on
song:play, near the flyover's landing, or at handoff — whichever first.
Machine commits and stingers defer during the intro; stop()/song-change
abort it. Packs without an intro behave as before.

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

* fix(venue-crowd): fall back to the loop when the intro fails to load

Codex preflight: a failed/timed-out intro left the song with no crowd
loop at all.

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

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

static/v3/index.html

@@ -1275,6 +1275,7 @@
          saved 'off'/'full' motion preference on first paint. -->
     <script defer src="/static/v3/venue-mood-fx.js"></script>
     <script defer src="/static/v3/venue-scene-3d.js"></script>
+    <script defer src="/static/v3/venue-crowd.js"></script>
     <script defer src="/static/v3/playlists.js"></script>
     <script defer src="/static/v3/audio-routing.js"></script>
     <script defer src="/static/v3/live-guitar-tone-source.js"></script>