Initial portal commit: landing + 9 AI-powered apps

Apps:
- dwg-rooms: extract room numbers from DWG/DXF
- dwg-counting: count symbols in PDF drawings (OpenCV template matching)
- contract-check: review PDF contracts against a checklist (Claude vision + Tesseract OCR fallback)
- email-drafter: bullet notes → polished Czech/English business emails
- invoice-extractor: PDF/image invoice → structured data → Excel
- translator: Czech-first translator across 19 languages with tone control
- vv-check: find inconsistent unit prices across VV sheets in one workbook
- vv-compare: diff original vs new VV files (changes / added / removed)
- feature-request: portal users submit ideas + sample files

Infrastructure:
- LiteLLM gateway with per-app virtual keys + budgets
- Langfuse observability
- Geist font, shared theme, cross-subdomain back link + theme sync via cookie/URL
- Caddy reverse proxy on *.klas.chat

vv-compare/main.py

@@ -0,0 +1,90 @@
+"""FastAPI: two Excel VVs (original + new) → comparison report Excel."""
+import logging
+import os
+import uuid
+from pathlib import Path
+
+from fastapi import FastAPI, File, HTTPException, UploadFile
+from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import FileResponse
+from fastapi.staticfiles import StaticFiles
+
+from vv_compare import compare, write_compare_report
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+app = FastAPI(title="VV Compare")
+app.add_middleware(CORSMiddleware, allow_origins=["*"],
+                   allow_methods=["*"], allow_headers=["*"])
+
+WORK_DIR = Path(os.getenv("WORK_DIR", "/tmp/vv-compare"))
+WORK_DIR.mkdir(parents=True, exist_ok=True)
+
+jobs: dict[str, dict] = {}
+
+
+@app.get("/")
+async def root():
+    return FileResponse("static/index.html")
+
+
+@app.post("/api/compare")
+async def do_compare(
+    original: UploadFile = File(...),
+    new: UploadFile = File(...),
+):
+    for f in (original, new):
+        suffix = Path(f.filename or "").suffix.lower()
+        if suffix not in (".xlsx", ".xlsm"):
+            raise HTTPException(400, "Podporované formáty: .xlsx, .xlsm")
+
+    job_id = str(uuid.uuid4())
+    job_dir = WORK_DIR / job_id
+    job_dir.mkdir()
+    orig_path = job_dir / f"original{Path(original.filename).suffix}"
+    new_path = job_dir / f"new{Path(new.filename).suffix}"
+    orig_path.write_bytes(await original.read())
+    new_path.write_bytes(await new.read())
+    logger.info("Job %s: original=%s, new=%s", job_id, original.filename, new.filename)
+
+    try:
+        result = compare(orig_path, new_path)
+    except Exception as exc:
+        logger.exception("Compare failed")
+        raise HTTPException(500, f"Porovnání selhalo: {exc}")
+
+    jobs[job_id] = {
+        "original_filename": original.filename,
+        "new_filename": new.filename,
+        "job_dir": str(job_dir),
+        "result": result,
+    }
+    return {"job_id": job_id, "result": result}
+
+
+@app.get("/api/report/{job_id}")
+async def report(job_id: str):
+    if job_id not in jobs:
+        raise HTTPException(404, "Úloha nenalezena")
+    job = jobs[job_id]
+    out_path = Path(job["job_dir"]) / "report.xlsx"
+    write_compare_report(
+        job["result"],
+        job.get("original_filename") or "puvodni.xlsx",
+        job.get("new_filename") or "novy.xlsx",
+        out_path,
+    )
+    return FileResponse(
+        str(out_path),
+        media_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+        filename="Porovnani_VV_puvodni_vs_novy.xlsx",
+    )
+
+
+@app.get("/health")
+async def health():
+    return {"status": "ok"}
+
+
+app.mount("/static", StaticFiles(directory="static"), name="static")