Gate precision: stop false-positives on art movements / events / starters

With landmarks now allowed, the remaining narration rejections were pure
false-positives: capitalized non-places the gate mistook for venues —
"Impressionism"/"Impressionist", "French Revolution", "Remember". Add art
movements, historical events/periods, and more sentence-starters to
_COMMON so grounded prose passes. A real invented venue (Cafe des
Mensonges) and the planted Eiffel Tower still fail.

Test: test_gate_ignores_art_movements_and_events.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/discoverroute/narrate/grounding.py

@@ -91,6 +91,22 @@ _COMMON = {
     "monument", "memorial", "library", "theatre", "theater", "cinema", "hall",
     "station", "court", "fountain", "statue", "tower", "gate", "house", "centre",
     "center", "city", "town", "village", "waterfront",
+    # art movements / styles a guide invokes — capitalized but NOT venues (the
+    # gate was rejecting whole narrations over "Impressionism"/"Impressionist").
+    "impressionism", "impressionist", "impressionists", "cubism", "cubist",
+    "surrealism", "surrealist", "expressionism", "expressionist", "romanticism",
+    "modernism", "minimalism", "realism", "symbolism", "futurism", "dadaism",
+    "fauvism", "pointillism", "abstraction", "bauhaus",
+    # historical events / periods / eras (capitalized, not places): "French
+    # Revolution", "the Belle Époque" etc.
+    "revolution", "revolutions", "empire", "republic", "monarchy", "reign",
+    "dynasty", "era", "age", "antiquity", "enlightenment", "reformation",
+    "belle", "époque", "epoque", "renaissance", "restoration", "occupation",
+    "war", "wars",
+    # more sentence-starters / imperatives the model opens clauses with
+    "remember", "consider", "watch", "listen", "recall", "observe", "sense",
+    "perhaps", "maybe", "indeed", "history", "culture", "tradition", "legend",
+    "myth", "legends", "myths", "everywhere", "somewhere", "anywhere",
 }
 
 _TOKEN_RE = re.compile(r"[A-Za-zÀ-ÖØ-öø-ÿ][A-Za-zÀ-ÖØ-öø-ÿ0-9'’.\-]*")

tests/test_narration.py

@@ -101,6 +101,21 @@ def test_geo_gazetteer_allows_landmarks_but_not_eiffel():
     assert not ok2 and any("Eiffel" in o for o in off2)
 
 
+def test_gate_ignores_art_movements_and_events():
+    """Capitalized non-places (art movements, historical events, sentence-starters)
+    must not trip the gate — they were sinking whole narrations live
+    ('Impressionism', 'French Revolution', 'Remember')."""
+    text = ("Remember the French Revolution as you pass Jardin des Plantes; the "
+            "Impressionism and Impressionist spirit lingers here.")
+    ok, off = grounding.verify_grounded(text, POIS, start_label="Bastille")
+    assert ok, off
+    # but a genuinely invented venue in the same prose still fails
+    ok2, off2 = grounding.verify_grounded(
+        "Remember the Impressionists at Café des Mensonges near Jardin des Plantes.",
+        POIS, start_label="Bastille")
+    assert not ok2 and any("Mensonges" in o for o in off2)
+
+
 def test_geo_gazetteer_still_blocks_invented_venue():
     """Loosening for districts must NOT let an invented venue through."""
     from discoverroute.narrate import gazetteer