test: mode registry consistency checks; fail fast if registry missing

Also documents the registry-driven mode integration in CLAUDE.md.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_mode_registry.py

@@ -0,0 +1,39 @@
+"""Consistency checks between the mode registry and the template/assets."""
+
+import re
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+REGISTRY = ROOT / "static" / "js" / "mode-registry.js"
+INDEX = ROOT / "templates" / "index.html"
+
+
+def _registry_modes() -> set[str]:
+    src = REGISTRY.read_text()
+    return set(re.findall(r"^\s{4}([a-z_]+):\s*\{", src, re.M))
+
+
+def test_registry_has_all_modes():
+    """The registry must declare a sane number of modes (28 at creation)."""
+    modes = _registry_modes()
+    assert len(modes) >= 28, f"registry lost modes: {sorted(modes)}"
+
+
+def test_registry_modes_have_partials():
+    """Every partial included by index.html must exist on disk."""
+    html = INDEX.read_text()
+    partials = set(re.findall(r"partials/modes/([\w.-]+)\.html", html))
+    for partial in partials:
+        assert (ROOT / "templates" / "partials" / "modes" / f"{partial}.html").exists(), (
+            f"index.html includes missing partial: {partial}"
+        )
+
+
+def test_no_orphan_mode_assets():
+    """Every modes/*.js and modes/*.css file is referenced somewhere."""
+    referenced = INDEX.read_text() + REGISTRY.read_text()
+    # ground_station_waterfall.js belongs to the satellite dashboard
+    referenced += (ROOT / "templates" / "satellite_dashboard.html").read_text()
+    for asset_dir, ext in [("static/js/modes", ".js"), ("static/css/modes", ".css")]:
+        for f in (ROOT / asset_dir).glob(f"*{ext}"):
+            assert f.name in referenced, f"orphaned mode asset: {f}"