Stage three: spells fly through your own eyes

The reel's first-person mode now shows the fight, not just the rooms.
The board flourishes' event map is recast into world space (fx3d):
fireballs, bolts, and thrown things streak caster to target as glowing
billboards; landings swell and fade; blows that land on YOU wash the
screen red and jolt the camera; warp-steps and teleports flash violet;
a hurled body glides fast and straight with its eyes held steady. Nine
paintable conjuration sprites ship at public/fx3d (spec for the artist
in research/), shown in the token workshop beside the masonry.

Three rough edges sharpened along the way: sprites now project through
warp mouths under the same rigid motion the rays use, clipped by the
depth buffer to the opening; fire and warp surfaces pull a different
texture slice per world cell so a long blaze reads as one; and the
replay camera only turns toward an actor its eyes could actually see.

Two more gifts: the reel can record its first-person canvas straight
to a downloadable WebM (⏺ save video), and the About tab now shows
visitors the way into the three workshops.

One buried mine defused: rAF hands frame-start times that can precede
the tween's own clock, and a zero-length turn divided by it — one NaN
facing poisoned every ray black and re-triggered the camera effect
forever. The tween clamps and guards its phases now.

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

research/fx3d-sprite-spec.md

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+# The conjuration sprites — a spec for the artist
+
+The first-person view (`/?fpv`, and the replay's "your eyes" mode) throws
+spell moments through the air as **billboard sprites**: flat images that
+always face the camera, drawn glowing in mid-air, occluded by walls, and
+scaled by distance. Nine sprites cover every spell moment in the game.
+Each lives at `packages/web/public/textures/../fx3d/<name>.png` — replace
+the file, refresh, done. The current files are placeholder radial glows;
+all nine are shown side by side at `/?tokens` under "The conjurations."
+
+## Technical requirements
+
+- **Format:** PNG with a transparent background. The transparent area is
+  essential — whatever is opaque is what flies.
+- **Size:** square, any resolution; 128×128 or 256×256 recommended. The
+  renderer scales freely and pixelates on magnification (the whole view
+  is deliberately chunky, like the wall textures).
+- **Drawn additively:** sprites are composited in "lighter" (additive)
+  mode over a dark dungeon, so dark pixels vanish and bright pixels glow.
+  Paint light-on-transparent; pure black will be invisible. Midtones read
+  as translucent light.
+- **No animation frames.** Each sprite is a single still. Motion comes
+  from the renderer: projectiles streak across the room, impacts swell
+  from small to large while fading out. Radially symmetric (or nearly so)
+  designs work best since the image does not rotate.
+- **Fills most of the canvas.** Leave only a small transparent margin;
+  the renderer sizes the sprite by its canvas, not its painted extent.
+
+## The nine sprites and where they appear
+
+| file | flies as | moment |
+| --- | --- | --- |
+| `fireball.png` | projectile | Fireball, Sudden Death, Blaster Wand — a ball of fire streaking caster → target |
+| `bolt.png` | projectile | Lightning Blast, Power Drain — a crackling bolt |
+| `waterbolt.png` | projectile | Waterbolt — a hurled gout of water |
+| `spark.png` | projectile | anything else that travels: thrown objects, bodies knocked back, dragged things — a neutral streak of force |
+| `burst.png` | impact | a fireball landing; victory fireworks — swells and fades |
+| `splash.png` | impact | waterbolt landing, stone turned to water |
+| `hit.png` | impact | damage landing on someone you can see; punches, claws |
+| `shimmer.png` | impact | teleports, warps, illusions, minds touched — the general "magic happened here" glimmer, violet by tradition |
+| `shield.png` | impact | an attack fully stopped; absorbed spells |
+
+Projectiles hold their size in flight (about a third of a wizard's
+height). Impacts start small and swell to roughly double while fading —
+so an impact painted as a ring or burst reads especially well.
+
+What the sprites do NOT need to carry: screen-wide flashes when YOU are
+hit (red), healed (green), or teleported (violet), and the camera shake —
+those are renderer effects, not images.