feat(db): add cross-culture name pool collision checking to validate-ron

New --check-name-collisions mode scans all culture-*.ron files and
reports given/family names appearing in multiple culture pools.
Exits 1 on collision with machine-readable output. Sprint 26 review
caught 6 overlaps manually — this automates the check.

Ticket: #665

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

tooling/validate-ron

@@ -3,20 +3,123 @@
 #
 # Usage:
 #   tooling/validate-ron <file.ron> <zone|culture>
+#   tooling/validate-ron --check-name-collisions <content/dir/>
 #
 # Examples:
 #   tooling/validate-ron content/global/zone-identity-spec.example.ron zone
 #   tooling/validate-ron content/global/culture-van-maanens-star.example.ron culture
+#   tooling/validate-ron --check-name-collisions content/global/
+#
+# --check-name-collisions:
+#   Scans all culture-*.ron files in the given directory. Extracts naming.given_names
+#   and naming.family_names pools from each file. Reports any name that appears in more
+#   than one culture's pool. Exits 1 on collision; exits 0 if no collisions found.
+#   Output is machine-readable (one collision per line).
 
 set -euo pipefail
 
+# --- Name collision mode --------------------------------------------------
+if [ "${1:-}" = "--check-name-collisions" ]; then
+    if [ $# -lt 2 ]; then
+        echo "Usage: tooling/validate-ron --check-name-collisions <directory>"
+        exit 1
+    fi
+    SCAN_DIR="$2"
+    if [ ! -d "$SCAN_DIR" ]; then
+        echo "Error: directory not found: $SCAN_DIR"
+        exit 1
+    fi
+    python3 - "$SCAN_DIR" <<'PYEOF'
+import sys
+import re
+import os
+import glob
+
+scan_dir = sys.argv[1]
+pattern = os.path.join(scan_dir, "culture-*.ron")
+files = sorted(glob.glob(pattern))
+
+if not files:
+    print(f"No culture-*.ron files found in: {scan_dir}")
+    sys.exit(0)
+
+def extract_names_from_block(text, field):
+    """Extract quoted string list from a named RON array field."""
+    # Match: field: [\n  "name", "name", ...\n]
+    # Handles multi-line arrays with comments inside.
+    pat = re.compile(
+        r'\b' + re.escape(field) + r'\s*:\s*\[([^\]]*)\]',
+        re.DOTALL
+    )
+    m = pat.search(text)
+    if not m:
+        return []
+    block = m.group(1)
+    # Strip line comments before extracting quoted strings
+    block = re.sub(r'//[^\n]*', '', block)
+    block = re.sub(r'/[^\n]*', '', block)  # single-slash RON comments
+    return re.findall(r'"([^"]+)"', block)
+
+# culture_id -> set of names (given + family, tracked separately for reporting)
+given_by_culture = {}
+family_by_culture = {}
+
+for fpath in files:
+    with open(fpath, 'r', encoding='utf-8') as f:
+        text = f.read()
+    # Extract culture id from the id: "..." field
+    id_m = re.search(r'\bid\s*:\s*"([^"]+)"', text)
+    culture_id = id_m.group(1) if id_m else os.path.basename(fpath)
+
+    given_by_culture[culture_id] = set(extract_names_from_block(text, 'given_names'))
+    family_by_culture[culture_id] = set(extract_names_from_block(text, 'family_names'))
+
+cultures = list(given_by_culture.keys())
+collisions_found = False
+
+# Check given_names collisions
+all_given_names = {}  # name -> list of cultures
+for culture, names in given_by_culture.items():
+    for name in names:
+        all_given_names.setdefault(name, []).append(culture)
+
+for name, cultures_with_name in sorted(all_given_names.items()):
+    if len(cultures_with_name) > 1:
+        collisions_found = True
+        print(f"COLLISION given_names: \"{name}\" in {', '.join(sorted(cultures_with_name))}")
+
+# Check family_names collisions
+all_family_names = {}  # name -> list of cultures
+for culture, names in family_by_culture.items():
+    for name in names:
+        all_family_names.setdefault(name, []).append(culture)
+
+for name, cultures_with_name in sorted(all_family_names.items()):
+    if len(cultures_with_name) > 1:
+        collisions_found = True
+        print(f"COLLISION family_names: \"{name}\" in {', '.join(sorted(cultures_with_name))}")
+
+if not collisions_found:
+    print(f"OK: no name collisions across {len(cultures)} culture(s): {', '.join(sorted(cultures))}")
+    sys.exit(0)
+else:
+    sys.exit(1)
+PYEOF
+    exit $?
+fi
+# --- End name collision mode ----------------------------------------------
+
 if [ $# -lt 2 ]; then
     echo "Usage: tooling/validate-ron <file.ron> <zone|culture>"
+    echo "       tooling/validate-ron --check-name-collisions <directory>"
     echo ""
     echo "Validates a RON file against the Rust struct schema."
     echo "Schema types:"
     echo "  zone    — ZoneSpec (zone identity spec)"
     echo "  culture — CultureProfile (culture profile)"
+    echo ""
+    echo "Name collision check:"
+    echo "  --check-name-collisions <dir>  Scan culture-*.ron files for shared name pool entries"
     exit 1
 fi