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/main.py

@@ -0,0 +1,120 @@
+import os
+from pathlib import Path
+
+from fastapi import FastAPI, HTTPException
+from fastapi.responses import FileResponse
+from fastapi.staticfiles import StaticFiles
+from openai import AsyncOpenAI
+from pydantic import BaseModel
+
+import backend.storage as storage
+from backend.models import extract_vars
+
+DIST = Path(__file__).parent.parent / "frontend" / "dist"
+OPENAI_MODEL = os.getenv("OPENAI_MODEL", "gpt-4.1")
+
+app = FastAPI()
+
+
+# ── Models ────────────────────────────────────────────────────────────────────
+
+class PresetBody(BaseModel):
+    name: str
+    description: str = ""
+    template: str
+
+
+class SettingsBody(BaseModel):
+    openai_api_key: str
+
+
+class RewriteBody(BaseModel):
+    prompt: str
+
+
+# ── Presets ───────────────────────────────────────────────────────────────────
+
+@app.get("/api/presets")
+def get_presets():
+    return {"presets": storage.list_presets()}
+
+
+@app.post("/api/presets", status_code=201)
+def create_preset(body: PresetBody):
+    variables = extract_vars(body.template)
+    return storage.create_preset(body.name, body.description, body.template, variables)
+
+
+@app.put("/api/presets/{preset_id}")
+def update_preset(preset_id: str, body: PresetBody):
+    variables = extract_vars(body.template)
+    result = storage.update_preset(preset_id, {
+        "name": body.name,
+        "description": body.description,
+        "template": body.template,
+        "variables": variables,
+    })
+    if result is None:
+        raise HTTPException(status_code=404, detail="Preset not found")
+    return result
+
+
+@app.delete("/api/presets/{preset_id}")
+def delete_preset(preset_id: str):
+    if not storage.delete_preset(preset_id):
+        raise HTTPException(status_code=404, detail="Preset not found")
+    return {"ok": True}
+
+
+# ── Settings ──────────────────────────────────────────────────────────────────
+
+@app.get("/api/settings")
+def get_settings():
+    key = storage.get_openai_key()
+    return {"openai_api_key_set": bool(key)}
+
+
+@app.post("/api/settings")
+def update_settings(body: SettingsBody):
+    storage.set_openai_key(body.openai_api_key)
+    return {"ok": True}
+
+
+# ── AI Rewrite ────────────────────────────────────────────────────────────────
+
+@app.post("/api/rewrite")
+async def rewrite_prompt(body: RewriteBody):
+    key = storage.get_openai_key()
+    if not key:
+        raise HTTPException(status_code=400, detail="OpenAI API key not configured")
+
+    client = AsyncOpenAI(api_key=key)
+    try:
+        response = await client.chat.completions.create(
+            model=OPENAI_MODEL,
+            messages=[
+                {
+                    "role": "system",
+                    "content": (
+                        "You are a prompt engineer. Rewrite the user's prompt to be clearer, "
+                        "more specific, and more effective for an AI assistant. "
+                        "Return only the rewritten prompt, no explanation."
+                    ),
+                },
+                {"role": "user", "content": body.prompt},
+            ],
+        )
+    except Exception as e:
+        raise HTTPException(status_code=502, detail=str(e))
+
+    return {"rewritten": response.choices[0].message.content}
+
+
+# ── SPA static serving (must be last) ────────────────────────────────────────
+
+if DIST.exists():
+    app.mount("/assets", StaticFiles(directory=DIST / "assets"), name="assets")
+
+    @app.get("/{full_path:path}")
+    def serve_spa(full_path: str):
+        return FileResponse(DIST / "index.html")