Fix .env loading for subagents, add LUMINA video + two new compositions

tools/base_tool.py now auto-loads .env at import time so API keys are
available even when tools are imported directly (fixes silent zero-key
fallback in subagents). Added LUMINA bioluminescent terrarium product
ad embed to README. Two new demo compositions: 37 Trillion (one-key
narrated explainer) and LUMINA (music-driven product ad, no narration).

tools/base_tool.py

@@ -19,6 +19,31 @@ from pathlib import Path
 from typing import Any, Callable, Optional
 
 
+def _load_dotenv() -> None:
+    """Load .env into os.environ once at import time.
+
+    This ensures API keys are available before any tool is instantiated,
+    even when tools are imported directly without going through the registry.
+    Only sets variables that are not already in the environment.
+    """
+    env_path = Path(__file__).resolve().parent.parent / ".env"
+    if not env_path.is_file():
+        return
+    with open(env_path, encoding="utf-8", errors="ignore") as f:
+        for line in f:
+            line = line.strip()
+            if not line or line.startswith("#") or "=" not in line:
+                continue
+            key, _, value = line.partition("=")
+            key = key.strip()
+            value = value.strip().strip("'\"")
+            if key and key not in os.environ:
+                os.environ[key] = value
+
+
+_load_dotenv()
+
+
 class ToolTier(str, Enum):
     CORE = "core"
     VOICE = "voice"