feat(editor-v2): vocab generator + cvar_list-derived JSON

build-vocab.py parses ./cvar_list (live L4D2 cvarlist dump, 2196 entries)
into static/data/srccfg-vocab.json — 1523 cvars + 671 commands.
Idempotent. Records the source-file SHA256 in the JSON header so
regenerations are auditable.

cvar_list is committed as a tracked data file so the generation is
reproducible from the repo alone.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

l4d2web/scripts/build-vocab.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+"""Convert ./cvar_list (cvarlist dump) to static/data/srccfg-vocab.json.
+
+Usage: ./l4d2web/scripts/build-vocab.py
+Reads from the repo root (auto-detected via this script's path).
+Writes idempotently. Run after regenerating cvar_list."""
+from __future__ import annotations
+
+import hashlib
+import json
+import pathlib
+import re
+import sys
+
+HERE = pathlib.Path(__file__).resolve().parent
+REPO_ROOT = HERE.parent.parent
+SOURCE = REPO_ROOT / "cvar_list"
+DEST = REPO_ROOT / "l4d2web" / "l4d2web" / "static" / "data" / "srccfg-vocab.json"
+
+
+def parse(text: str) -> tuple[list[dict], list[dict]]:
+    cvars: list[dict] = []
+    commands: list[dict] = []
+    for raw in text.splitlines()[2:]:  # skip "cvar list" + "--------…"
+        if not raw.strip():
+            continue
+        parts = [p.strip() for p in re.split(r"\s*:\s*", raw, maxsplit=3)]
+        if len(parts) < 3:
+            continue
+        name = parts[0]
+        value = parts[1]
+        desc = parts[3] if len(parts) >= 4 else ""
+        target = commands if value == "cmd" else cvars
+        target.append({"name": name, "desc": desc} if desc else {"name": name})
+    return cvars, commands
+
+
+def main() -> int:
+    if not SOURCE.exists():
+        print(f"ERROR: {SOURCE} not found", file=sys.stderr)
+        return 1
+    text = SOURCE.read_text(encoding="utf-8", errors="replace")
+    cvars, commands = parse(text)
+    src_sha = hashlib.sha256(text.encode("utf-8")).hexdigest()
+    payload = {
+        "version": 1,
+        "generated_from": "cvar_list",
+        "source_sha256": src_sha,
+        "cvars": cvars,
+        "commands": commands,
+    }
+    DEST.parent.mkdir(parents=True, exist_ok=True)
+    DEST.write_text(json.dumps(payload, indent=2, sort_keys=False) + "\n", encoding="utf-8")
+    print(f"wrote {DEST}: {len(cvars)} cvars + {len(commands)} commands")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())