- Rename /television route + public assets to /tv (shorter, link to it
  from the docs header next to WordArt).
- Query param renamed to ?model=<id> (was ?tv=<id> — reads better
  alongside /tv).
- Brighter scene lighting (directional 4.5→6.5, ambient 0.55→0.9) plus
  a ground <poly-plane> below each TV with cast-shadow on the mesh, so
  the bottom of every TV sits visibly on the floor.

Element changes to support the floor:
- PolyShapeElement now forwards `cast-shadow` / `receive-shadow` to
  scene.add (mirrors <poly-mesh>) and `exclude-from-auto-center` so
  ground planes don't skew the scene's auto-center calculation.
- PolyShapeElement gains an attributeChangedCallback so transform attrs
  (position/scale/rotation/shadow) propagate after mount — the floor is
  re-positioned per TV from the script side once the mesh has loaded.
- PolyPlaneElement: new `offset` attribute, defaulting to 0 so the
  plane is centered at the element's local origin. The underlying
  planePolygons helper defaulted to size*2 because it was authored as
  a transform-control drag handle.

Camera-element runtime fix:
- PolyPerspectiveCameraElement / PolyOrthographicCameraElement
  attributeChangedCallback now correctly locates the scene as a
  descendant (`this.querySelector('poly-scene')`) rather than an
  ancestor. The previous walk-up version always found null and
  applyCamera was never called, so runtime rot-x/rot-y/zoom changes
  were no-ops in vanilla.

Tuning:
- TV mesh gets `auto-center` so its bbox center IS mesh-local (0,0,0).
- Floor's per-preset Z is derived from the mesh's minZ on load.
- Per-TV cam.rotY/zoom dialed in by hand for each set (pixel TV at
  rotY 245 / zoom 10 for a 3/4 view that doesn't crop).

- Retro stack screen 1: append poly 216 to the polyIndices array (user
  identified it as part of that CRT's bezel strip; was missing).
- Floor shadow attempt: receiver-shadow on the floor + scene shadow
  config wired up cleanly, but the projected shadow SVG lands at wrong
  scene coords for our auto-centered TV + excludeFromAutoCenter floor
  combination. Vanilla dropped the legacy ground-shadow fallback for
  three.js parity, so a caster with no receiver draws nothing. Leaving
  the floor as a non-receiver for now with a TODO; lighting + floor
  geometry still ship.

The receiver-shadow SVG sits at the floor plane plus `shadow.lift`
(default 0.05 world units = 2.5 CSS px). On a big 400-world-unit floor
viewed at a normal-angle camera (rotX 70), that razor-thin gap z-fought
with the floor itself and the shadow only showed from straight overhead.
A 1 world unit (50 CSS px) lift puts the shadow clearly in front at
every angle the camera reaches.

The first CRT's actual screen polygons are 212–216 — 211 is an adjacent
bezel face the iframe-placement code was averaging into the plane,
shifting the iframe off the screen. Restricting to 212–216 lands the
iframe on the visible glass.

placementFromPolygons now takes an optional liftOverride; the TvScreen
config exposes it as `lift`. The retro stack's CRT screens already
model the front glass surface, so a small negative lift (−0.6 world
units) seats the iframe inside the bezel instead of in front of it.

The default lift formula (0.2 + 0.01 * max(w,h)) still applies for
every other TV — those polygons mark the screen plane itself, so the
iframe sitting slightly in front of them reads as the picture surface.

…rtifacts)

The 'floating quad' I attributed to receive-shadow earlier turned out to
be the monitor.glb's back panel authored at an offset position — present
even without receive-shadow.

Self-shadows on textured receivers are computed correctly but the
texturedReceiver code reduces opacity to mimic three.js's 'darken to
ambient-only' (`effOp = opacity * (1 - (ambient/total)^(1/2.4))`).
With our bright light (dir 6.5, ambient 0.9) that pushed shadow alpha
to ~0.32, which read as nearly-invisible 'white-ish' on textured TVs.
Bumping the input opacity to 0.95 lands the effective alpha at ~0.55
and the self-shadows now read as actually dark.

…ead dark

- Lift 1 → 0.1 world units. The bigger value was detaching shadows
  visibly from their receivers; 0.1 (5 CSS px) still clears z-fighting
  but reads as flush with the floor / bezel.
- Ambient intensity 0.9 → 0.4. The texture-receiver code caps shadow
  alpha at `opacity * (1 - (ambient/total)^(1/2.4))` to mimic three.js's
  'darken to ambient-only' lighting model. With ambient=0.9 the cap
  pushed effective shadow alpha to ~0.32 — visibly faint / 'white-ish'
  on the TV's own faces. Lower ambient = darker possible shadows; 0.4
  hits the polycss default and lets self-shadows read as properly dark.

- Bottom-centre toggle switches between <poly-orbit-controls> and
  <poly-first-person-controls>. FPV mounts with WASD/jump/look and a
  hint label appears on the right side of the pill while active.
- Orbit zoom range widened to [1, 200] so users can zoom out far past
  each TV's default zoom.

- Drop receive-shadow from the TV mesh: the texture-receiver darkening
  reads as 'white-ish' (capped at ambient brightness) and visible
  self-shadows weren't worth the cost.
- FPV mode now matches the gallery's defaults: move-speed 30,
  jump-velocity 25, gravity 60, eye-height 6, look-sensitivity 0.15.
  Also switches camera perspective to 2000 while FPV is active (the
  same FPV_PERSPECTIVE the gallery and builder use) for a wider FOV;
  restores to 32000 when going back to Orbit.

…pawn)

Entering FPV used to drop the camera at scene origin (where the TV
sits, since the scene is auto-centered) — so the player was INSIDE the
TV with a face full of bezel.

Now matching gallery's spawn behaviour:
- Save + drop scene's auto-center attribute on entry, restore on exit.
- Compute TV bbox from the loaded mesh handle, derive a spawn target
  one mesh-span behind the TV along the current rotY look direction,
  set it on the camera so the controls' initializeOriginFromTarget
  uses that as the seed.
- Remove target on exit so orbit returns to its scene-origin pivot.

…pective changes