feat(totalannihilation): add Megatank unit with multi-barrel weapons and rebalance combat

- Introduce Megatank: medium commander with Twin 150mm Cannon and Side Rocket Pods
- Implement multi-barrel weapon system (barrels + barrelSpacing) in TALogic and TARules
- Lower DEFENCE_MIN_SKILL from 4 to 3; make first Laser Tower proactive, not reactive
- Rebalance unit triangle: Tank now counters Rocket Tank; rockets weak vs vehicle armour
- Re-seed campaign missions m05 (67890) and m06 (80808) with updated maps and briefings
- Skirmish default theme uses rules default (tropics) instead of hardcoded grasslands
- Add intro video before main menu
- Update sprite docs and verification tests for new balance

data/totalannihilation-artwork.json

@@ -67,7 +67,7 @@
     },
     "icons": {
       "key": "ta-icons", "path": null, "kind": "icon",
-      "frameWidth": 44, "frameHeight": 44, "cols": 10,
+      "frameWidth": 64, "frameHeight": 64, "cols": 10,
       "rows": 4
     }
   },

src/games/totalannihilation/TAHud.js

@@ -273,6 +273,9 @@ export default class TAHud {
     this._clearGrid();
     const s = this.scene;
     const army = this.state.armies[this.playerArmy];
+    // Real art or the procedural fallback (TAArt.js always supplies one or the other), so this
+    // is only null for a def that predates the `icon` field — see the fallback layout below.
+    const iconKey = this.view.sheetKeys?.icons;
     options.forEach((def, i) => {
       const col = i % GRID_COLS, row = Math.floor(i / GRID_COLS);
       // The container is placed at the button's CENTRE, not its top-left — see below.
@@ -286,13 +289,23 @@ export default class TAHud {
       // child here is centred on (0,0) so the visual and the hit area coincide.
       const box = s.add.rectangle(0, 0, BTN_W, BTN_H, affordable ? 0x22304a : 0x1a2130, 1)
         .setStrokeStyle(2, affordable ? EDGE : 0x2a3244);
-      const label = s.add.text(0, -BTN_H / 2 + 12, shortName(def.name), {
-        fontFamily: FONT, fontSize: '20px', color: affordable ? TEXT : '#5d6b80',
+      const children = [box];
+      const hasIcon = iconKey != null && def.icon != null;
+      // The icon carries the button's identity at a glance once one exists; name and cost drop
+      // underneath it rather than owning the whole button the way they did before icons.
+      if (hasIcon) {
+        const icon = s.add.image(0, -18, iconKey, def.icon).setDisplaySize(36, 36);
+        if (!affordable) icon.setAlpha(0.5);
+        children.push(icon);
+      }
+      const label = s.add.text(0, hasIcon ? 2 : -BTN_H / 2 + 12, shortName(def.name), {
+        fontFamily: FONT, fontSize: hasIcon ? '14px' : '20px', color: affordable ? TEXT : '#5d6b80',
       }).setOrigin(0.5, 0);
-      const cost = s.add.text(0, -BTN_H / 2 + 44, `${def.cost.mass}m ${def.cost.energy}e`, {
-        fontFamily: FONT, fontSize: '15px', color: affordable ? DIM : '#4e5a6d',
+      const cost = s.add.text(0, hasIcon ? 18 : -BTN_H / 2 + 44, `${def.cost.mass}m ${def.cost.energy}e`, {
+        fontFamily: FONT, fontSize: hasIcon ? '12px' : '15px', color: affordable ? DIM : '#4e5a6d',
       }).setOrigin(0.5, 0);
-      c.add([box, label, cost]);
+      children.push(label, cost);
+      c.add(children);
       c.setSize(BTN_W, BTN_H);
       c.setInteractive({ useHandCursor: true });
       c.on('pointerover', () => box.setFillStyle(affordable ? 0x2e3f5f : 0x1a2130, 1));

src/games/totalannihilation/sprites.md

@@ -30,14 +30,14 @@ capacity the verify script holds every `frame` index to, and it is measured off
 
 | Sheet name (JSON key) | Texture key | Cell | Cols | Contents |
 |---|---|---|---|---|
-| `arm-units` | `ta-arm-units` | 64×64 | 8 | ARM mobile units |
-| `core-units` | `ta-core-units` | 64×64 | 8 | CORE mobile units |
+| `arm-units` | `ta-arm-units` | 128×128 | 8 | ARM mobile units |
+| `core-units` | `ta-core-units` | 128×128 | 8 | CORE mobile units |
 | `arm-structures` | `ta-arm-structures` | 192×192 | 6×4 | ARM buildings |
 | `core-structures` | `ta-core-structures` | 192×192 | 6×4 | CORE buildings |
 | `terrain-grasslands` | `ta-terrain-grasslands` | 64×64 | 9 | Grassland tiles |
 | `terrain-snowfields` | `ta-terrain-snowfields` | 64×64 | 9 | Snow tiles |
 | `terrain-tropics` | `ta-terrain-tropics` | 64×64 | 9 | Jungle tiles |
-| `icons` | `ta-icons` | 44×44 | 10 | Command/build glyphs |
+| `icons` | `ta-icons` | 64×64 | 10 | Command/build glyphs — shared, NOT per-army |
 
 Frames are numbered **left to right, then top to bottom**, starting at 0.
 
@@ -228,24 +228,69 @@ The theme then appears in the skirmish setup screen automatically.
 
 ---
 
-## Icons (44×44 cells, 10 per row)
+## Icons (64×64 cells, 10 per row)
 
 Build-menu and command glyphs. Frame numbers come from each def's `icon` in the rules JSON
 and from `commandIcons`, so this table is a reflection of that file, not a second source of
-truth. Purely decorative today — the build menu labels itself from unit names — so this sheet
-is the lowest priority of the eight.
+truth.
+
+**Shared across both armies — this is the one sheet that does NOT get the "paint every army's
+sheet in its own finished colours" treatment** from the top of this doc. There's a single
+`icons` entry in the artwork JSON, not an `arm-icons`/`core-icons` pair, and the same frame
+renders in either player's build menu. Paint it in a neutral palette (dark plate + light
+linework is what the procedural fallback already does) rather than ARM blue or CORE red/orange.
+
+**Wired into the build menu** (`TAHud._drawGrid`, since 2026-08-16): every button in the
+build/production grid — buildings AND units — now draws this sheet's `def.icon` frame above the
+shortened name and cost, at a **36×36 display size**. The command bar (Move/Attack/Patrol/…)
+still renders text-only for now; its glyphs (frames 20–29) only exist for the procedural
+fallback painter today.
+
+**The 64×64 source is intentionally bigger than that 36×36 display size.** Painting at exactly
+the display size (the old 44×44 spec was already close to that trap) means every icon gets
+upscaled a little and softens; painting bigger and letting Phaser scale down is what keeps it
+crisp. Draw at the full 64×64 canvas — don't pre-shrink your art to "look right" at a smaller
+preview size.
 
 | Frames | Contents |
 |---|---|
 | 0–9 | Units: commander, infantry, sniper, jeep, tank, rocket tank, rocket trooper, construction vehicle, fighter, bomber |
 | 10–16 | Buildings: energy gen, mass gen, barracks, vehicle plant, laser tower, missile launcher, advanced vehicle plant |
 | 17–19 | Overflow: hover constructor (unit), airfield, radar tower |
-| 30–31 | Advanced radar, radar jammer |
 | 20–29 | Commands: move, attack, attack-move, stop, hold, patrol, guard, assist, repair, rally |
+| 30–31 | Advanced radar, radar jammer |
+| 32 | Megatank (unit) |
 
 Row 0 filled up before the Airfield units were added, which is why the hover constructor sits
 next to the buildings at 17 rather than with the other units. Nothing reads a row as a
-category — only the `icon` numbers matter.
+category — only the `icon` numbers matter. Frames 33–39 are free.
+
+### Painting priority: buildings the Commander and Construction Vehicle put up
+
+This is the set that actually appears in the build-menu grid during a normal game — the union
+of everything `commander`, `constructor` and `hoverconstructor` can build — in a sensible
+painting order (the 8 the Commander itself can queue from turn one, then the 3 that need a
+Construction Vehicle or Hover Constructor first):
+
+| Frame | Building | Also needs a Constructor? | Footprint |
+|---|---|---|---|
+| 10 | Energy Generator | no — Commander builds it too | 2×2 |
+| 11 | Mass Generator | no | 2×2 |
+| 12 | Barracks | no | 3×3 |
+| 13 | Vehicle Plant | no | 3×3 |
+| 14 | Laser Tower | no | 1×1 |
+| 15 | Missile Launcher | no | 2×2 |
+| 18 | Airfield | no | 3×3 |
+| 19 | Radar Tower | no | 2×2 |
+| 16 | Advanced Vehicle Plant | **yes** | 4×4 |
+| 30 | Advanced Radar | **yes** | 2×2 |
+| 31 | Radar Jammer | **yes** | 2×2 |
+
+Draw each as a simplified, high-contrast read of its full structure-sheet art (see Structure
+sheets below), not a literal crop of it — a 128–192px building shrunk straight down to 64px
+loses its silhouette to surface detail. Keep the same silhouette and colour language (Laser
+Tower's plinth-and-emitter, the Radar family's dish/mast/broken-rings distinction, etc.) so an
+icon and its full-size building are still recognisably the same thing at a glance.
 
 ---