Initial commit: prompt template manager

React + Tailwind frontend, FastAPI backend, settings.json storage.
Supports preset CRUD, live variable filling, and AI rewrite via OpenAI.

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

backend/storage.py

@@ -0,0 +1,73 @@
+import json
+import secrets
+from datetime import datetime, timezone
+from pathlib import Path
+
+SETTINGS_PATH = Path(__file__).parent.parent / "settings.json"
+
+
+def _now():
+    return datetime.now(timezone.utc).isoformat().replace("+00:00", "Z")
+
+
+def _read():
+    if not SETTINGS_PATH.exists():
+        return {"openai_api_key": "", "presets": []}
+    return json.loads(SETTINGS_PATH.read_text(encoding="utf-8"))
+
+
+def _write(data):
+    tmp = SETTINGS_PATH.with_suffix(".tmp")
+    tmp.write_text(json.dumps(data, indent=2), encoding="utf-8")
+    tmp.replace(SETTINGS_PATH)
+
+
+def list_presets():
+    return _read()["presets"]
+
+
+def create_preset(name, description, template, variables):
+    data = _read()
+    preset = {
+        "id": secrets.token_hex(4),
+        "name": name,
+        "description": description,
+        "template": template,
+        "variables": variables,
+        "created_at": _now(),
+        "updated_at": _now(),
+    }
+    data["presets"].append(preset)
+    _write(data)
+    return preset
+
+
+def update_preset(preset_id, fields):
+    data = _read()
+    for p in data["presets"]:
+        if p["id"] == preset_id:
+            p.update(fields)
+            p["updated_at"] = _now()
+            _write(data)
+            return p
+    return None
+
+
+def delete_preset(preset_id):
+    data = _read()
+    before = len(data["presets"])
+    data["presets"] = [p for p in data["presets"] if p["id"] != preset_id]
+    if len(data["presets"]) == before:
+        return False
+    _write(data)
+    return True
+
+
+def get_openai_key():
+    return _read().get("openai_api_key", "")
+
+
+def set_openai_key(key: str):
+    data = _read()
+    data["openai_api_key"] = key
+    _write(data)