HUD pass, weapon and trinket rework, and font arrows

HUD:
- Hotbars fit a quarter of the screen, dropping to small then tiny slots
  (thinner outlines when tiny), with cooldown bars matching their size.
- HUD elements are drawn on their own layer and composited at one
  opacity: hotbar slots are see-through until hovered, the rest fade
  while hovered.
- Rival windows fit the right column in at most two rows, shrinking
  icons then font, then dropping icons for name, health and ping bars.
- Tooltips number equipped items' slots and say Recoil for weapons that
  only push back. Previews use arrows, spread uses degrees.
- Crosshair fills in and shakes with charge, and weapons shake after
  firing until their cooldown ends. DPS and speed meters off by default.

Gameplay:
- Dual Wield stacks: each copy fires another recently held weapon from
  a fanned off-hand, at its own level's cut.
- Flamethrower: no slowing, smaller fireball with some recoil, and an
  airblast that knocks others away.
- Iron Weights slam on any landing faster than a plain fall (platforms
  too), stacking radius and damage, and speeding fast falls.
- Stuck arrows are one-way ledges until they fade, matching their
  (slightly larger) hit size. Attacks now collide with slopes.
- Halved Tesla Coil, Recoil Coil, Diazepam, Shock Absorber, Feather and
  screenshake values.

Art and tools:
- Weapon and trinket icons merged into one sheet each (normal, small,
  tiny), cells in catalog order. Grimoire wisps stand upright.
- Fonts gain the degree sign and four arrows, decoded from UTF-8.
- Menu fighter preview walks at quarter speed.
- Unequip from either catalog tab by right click or gamepad.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/effects.cpp

@@ -12,6 +12,8 @@ constexpr float FLASH_CROSS = 0.5f;
 constexpr float FLASH_LENGTH = 16;
 constexpr float FLASH_LIFE = 0.05f;
 constexpr float FLASH_WIDTH = 6;
+constexpr float RING_LIFE = 0.3f;
+constexpr int RING_WIDTH = 2;
 constexpr float AFTERIMAGE_LIFE = 0.12f;
 constexpr float NUMBER_GAP = 8;
 constexpr float POPUP_FADE = 0.4f;
@@ -28,9 +30,9 @@ constexpr float POPUP_SPREAD = 40;
 constexpr float PARTICLE_OUTLINE = 1;
 constexpr float PARTICLE_RANDOM_MIN = 0.4f;
 constexpr float SHAKE_DECAY = 2.5f;
-constexpr float SHAKE_LIMIT = 12;
-constexpr float SHAKE_MAX = 10;
-constexpr float SHAKE_TRAUMA_MAX = 3;
+constexpr float SHAKE_LIMIT = 6;
+constexpr float SHAKE_MAX = 5;
+constexpr float SHAKE_TRAUMA_MAX = 1.5f;
 
 // Adds to one of the effect lists, dropping its oldest once it holds EFFECTS_MAX, so a busy fight can't flood the
 // screen (or the renderer) with leftovers.
@@ -120,6 +122,11 @@ void Effects::flash_spawn(Vec2 position, float angle, float size, Color color)
     effect_add(flashes, Flash{color, position, angle, FLASH_LIFE, size});
 }
 
+void Effects::ring_spawn(Vec2 position, float radius, Color color)
+{
+    effect_add(rings, Ring{color, position, RING_LIFE, radius});
+}
+
 void Effects::dps_record(int amount)
 {
     hits.push_back({ticks * TICK, amount});
@@ -157,6 +164,10 @@ void Effects::update()
         flash.life -= TICK;
     std::erase_if(flashes, [](Flash& flash) { return flash.life <= 0; });
 
+    for (Ring& ring : rings)
+        ring.life -= TICK;
+    std::erase_if(rings, [](Ring& ring) { return ring.life <= 0; });
+
     for (Afterimage& afterimage : afterimages)
         afterimage.life -= TICK;
     std::erase_if(afterimages, [](Afterimage& afterimage) { return afterimage.life <= 0; });
@@ -198,6 +209,15 @@ void Effects::draw(Game& game)
         renderer.line_draw(flash.position - across, flash.position + across, width * FLASH_CROSS, flash.color);
     }
 
+    // Each ring eases out to its full radius as it fades.
+    for (Ring& ring : rings)
+    {
+        float fade = ring.life / RING_LIFE;
+        float radius = ring.radius * (1 - fade * fade);
+        for (int i = 0; i < RING_WIDTH; i++)
+            renderer.ring_draw(ring.position, std::max(1.0f, radius - i), color_fade(ring.color, fade));
+    }
+
     // Each particle shrinks and fades out. The outline is four strips so the fading core never shows it through.
     for (Particle& particle : particles)
     {
@@ -238,5 +258,6 @@ void Effects::clear()
     hits.clear();
     particles.clear();
     popups.clear();
+    rings.clear();
     shake = 0;
 }