feat(ModularBot): rammer movement + averaged-lead gun, 12 guns

- Ram movement: drive straight at enemy (not wired, needs selector)
- Averaged-lead gun: mean of linear+circular+wall-bounce predictions
- 12 guns total, battle-tested

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

common_libs/guns/averaged_lead.nim

@@ -0,0 +1,37 @@
+## Averaged-lead gun: mean prediction from linear, circular, and wall-bounce guns.
+## Smooths noise when enemy movement is between analytical models.
+
+import gun_harness/gun_interface
+import guns/linear
+import guns/circular
+import guns/wall_bounce
+
+type AveragedLeadGun* = object
+  linear:     LinearGun
+  circular:   CircularGun
+  wallBounce: WallBounceGun
+  cachedTick: int
+  cachedPred: GunPrediction  # per-tick cache; ponytail: single cache, extend if multi-power needed
+
+proc initAveragedLeadGun*(): AveragedLeadGun =
+  AveragedLeadGun(wallBounce: initWallBounceGun())
+
+proc predict*(g: var AveragedLeadGun, state: WorldState, bulletSpeed: float): GunPrediction =
+  if state.tick == g.cachedTick:
+    return g.cachedPred
+
+  let lp = g.linear.predict(state, bulletSpeed)
+  let cp = g.circular.predict(state, bulletSpeed)
+  let wp = g.wallBounce.predict(state, bulletSpeed)
+
+  var px = (lp.x + cp.x + wp.x) / 3.0
+  var py = (lp.y + cp.y + wp.y) / 3.0
+  px = clamp(px, BotRadius, state.arenaWidth  - BotRadius)
+  py = clamp(py, BotRadius, state.arenaHeight - BotRadius)
+
+  g.cachedTick = state.tick
+  g.cachedPred = GunPrediction(x: px, y: py)
+  g.cachedPred
+
+proc onResult*(g: var AveragedLeadGun, e: FeedbackEvent) =
+  discard  # analytical average — no learning