fix(assets): address PR #119 review round 2 — biomes.toml, legend, profile table

1. Add 5 extended atmosphere colors to biomes.toml (globe renderer reads
   from toml, not body_def) — cold_arid, hot_arid, tropical, boreal,
   temperate_terminator. Remove dead martian entry. Slightly differentiate
   colors from base classes.
2. Fix profile table raw identifiers — apply .replace('_', ' ') to class
   field in wiki body pages.
3. Fix legend text overflow — truncate labels with ellipsis when step
   size is too narrow for full text.
4. Fix title panel underscores — use .replace('_', ' ') instead of
   .replace('_ringed', '').

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tooling/planet-gen/render_heightmap.py

@@ -282,7 +282,7 @@ def _render_title(img: Image.Image, body_def: dict) -> Image.Image:
 
     name   = body_def.get("name") or body_def.get("id", "Unknown")
     bid    = body_def.get("id", "")
-    pclass = body_def.get("planet_class", "").replace("_ringed", "")
+    pclass = body_def.get("planet_class", "").replace("_", " ")
     star   = body_def.get("star", {})
     orbit  = body_def.get("orbit", {})
     phys   = body_def.get("physical", {})
@@ -370,10 +370,19 @@ def _render_legend(img: Image.Image, terrain: dict) -> Image.Image:
     max_step = (OUT_W - 2 * pad_x) // max(max_items, 1)
     step = min(int(108 * UI_SCALE), max_step)
 
+    # Max label width = step minus swatch minus gaps
+    max_label_px = step - sw - gap - int(4 * UI_SCALE)
+
     lx = pad_x
     for label, rgb in items:
         draw.rectangle([(lx, leg_y), (lx + sw, leg_y + sh)], fill=rgb)
-        draw.text((lx + sw + gap, leg_y), label,
+        # Truncate label to fit allocated space
+        display = label
+        while display and draw.textlength(display, font=font) > max_label_px:
+            display = display[:-1]
+        if display != label and display:
+            display = display[:-1] + "…"
+        draw.text((lx + sw + gap, leg_y), display,
                   fill=(185, 192, 205), font=font)
         lx += step