Server: Add launcher meta system for incremental updates

- Create versions/ folder structure for new format builds
- Generate meta.json with SHA256 hashes for each file
- Add endpoints:
  - GET /launcher/meta - list all versions with meta
  - GET /launcher/meta/{version} - meta for specific version
  - POST /launcher/diff - get diff between local and server files
  - GET /launcher/file/{version}/{path} - download individual file
  - GET /launcher/download/zip/{version} - download full ZIP for new install
- Legacy builds (ZIP files) remain unchanged

server/main.py

@@ -5,6 +5,7 @@ from contextlib import asynccontextmanager
 from datetime import datetime
 from pathlib import Path
 from urllib.parse import urlparse
+from typing import Optional
 
 import httpx
 import json
@@ -34,6 +35,7 @@ logger = structlog.get_logger(__name__)
 manifest_cache = TTLCache(maxsize=100, ttl=300)
 
 BUILDS_DIR = Path("builds")
+VERSIONS_DIR = BUILDS_DIR / "versions"
 
 # IP Filtering Configuration
 import os
@@ -794,6 +796,94 @@ def is_new_format(filename: str) -> bool:
     return filename.startswith("ZernMC-win-")
 
 
+# ====================== ЛАУНЧЕР МЕТА СИСТЕМА ======================
+
+def calculate_file_hash(file_path: Path) -> str:
+    """Calculate SHA256 hash of a file"""
+    import hashlib
+    hash_sha = hashlib.sha256()
+    with open(file_path, 'rb') as f:
+        while chunk := f.read(8192):
+            hash_sha.update(chunk)
+    return hash_sha.hexdigest()
+
+
+def scan_launcher_version(version: str) -> Optional[dict]:
+    """Scan a launcher version directory and return meta"""
+    version_path = VERSIONS_DIR / version
+    
+    if not version_path.exists() or not version_path.is_dir():
+        return None
+    
+    meta_path = version_path / "meta.json"
+    
+    # Check cache first
+    if meta_path.exists():
+        try:
+            import json
+            with open(meta_path, 'r', encoding='utf-8') as f:
+                return json.load(f)
+        except Exception:
+            pass
+    
+    # Generate meta
+    files = []
+    for file_path in version_path.rglob("*"):
+        if file_path.is_file() and file_path.name != "meta.json":
+            rel_path = str(file_path.relative_to(version_path))
+            stat = file_path.stat()
+            file_hash = calculate_file_hash(file_path)
+            files.append({
+                "path": rel_path,
+                "size": stat.st_size,
+                "hash": f"sha256:{file_hash}"
+            })
+    
+    meta = {
+        "version": version,
+        "type": "new",
+        "release_date": datetime.utcnow().isoformat(),
+        "files": files
+    }
+    
+    # Save meta
+    try:
+        import json
+        with open(meta_path, 'w', encoding='utf-8') as f:
+            json.dump(meta, f, indent=2)
+    except Exception as e:
+        logger.warning(f"Failed to save launcher meta for {version}: {e}")
+    
+    return meta
+
+
+def get_launcher_versions() -> list:
+    """Get list of available launcher versions with meta"""
+    if not VERSIONS_DIR.exists():
+        return []
+    
+    versions = []
+    for version_dir in VERSIONS_DIR.iterdir():
+        if version_dir.is_dir():
+            meta = scan_launcher_version(version_dir.name)
+            if meta:
+                versions.append({
+                    "version": version_dir.name,
+                    "meta": meta
+                })
+    
+    versions.sort(key=lambda x: x["version"], reverse=True)
+    return versions
+
+
+def get_launcher_version_meta(version: str) -> Optional[dict]:
+    """Get meta for specific launcher version"""
+    return scan_launcher_version(version)
+
+
+# ====================== END ЛАУНЧЕР МЕТА СИСТЕМА ======================
+
+
 def get_available_zips() -> list:
     """Get list of available zip archives (new format only)"""
     if not BUILDS_DIR.exists():
@@ -998,6 +1088,102 @@ async def download_launcher_zip(filename: str):
     )
 
 
+# ====================== ЛАУНЧЕР МЕТА ЭНДПОИНТЫ ======================
+
+@app.get("/launcher/meta")
+async def get_launcher_meta_list():
+    """Get list of all launcher versions with meta (new format)"""
+    versions = get_launcher_versions()
+    return {
+        "versions": [
+            {"version": v["version"], "meta": v["meta"]} 
+            for v in versions
+        ]
+    }
+
+
+@app.get("/launcher/meta/{version}")
+async def get_launcher_version_meta(version: str):
+    """Get meta for specific launcher version"""
+    meta = get_launcher_version_meta(version)
+    if not meta:
+        raise HTTPException(404, f"Version {version} not found or not in new format")
+    return meta
+
+
+@app.post("/launcher/diff")
+async def get_launcher_diff(request: Request):
+    """Get diff for launcher update - compare local files with server version"""
+    body = await request.json()
+    
+    # Get latest version
+    versions = get_launcher_versions()
+    if not versions:
+        raise HTTPException(404, "No versions available")
+    
+    latest = versions[0]
+    meta = latest["meta"]
+    
+    # Build hash map from client
+    client_hashes = body  # {filename: hash, ...}
+    
+    to_download = []
+    to_delete = []
+    
+    # Find new/updated files
+    server_files = {f["path"]: f for f in meta["files"]}
+    
+    for path, file_info in server_files.items():
+        if path not in client_hashes:
+            to_download.append(file_info)
+        elif client_hashes[path] != file_info["hash"]:
+            to_download.append(file_info)
+    
+    # Find deleted files (files on server but not in client)
+    for path in client_hashes:
+        if path not in server_files:
+            to_delete.append(path)
+    
+    return {
+        "version": meta["version"],
+        "to_download": to_download,
+        "to_delete": to_delete
+    }
+
+
+@app.get("/launcher/file/{version}/{file_path:path}")
+async def get_launcher_file(version: str, file_path: str, request: Request):
+    """Download a specific file from a launcher version"""
+    full_path = VERSIONS_DIR / version / file_path
+    
+    # Security: prevent path traversal
+    if ".." in file_path:
+        raise HTTPException(403, "Invalid file path")
+    
+    if not full_path.exists() or not full_path.is_file():
+        raise HTTPException(404, "File not found")
+    
+    return FileResponse(full_path, direct_passthrough=True)
+
+
+@app.get("/launcher/download/zip/{version}")
+async def download_launcher_zip_version(version: str):
+    """Download full ZIP for specific version (for new installs)"""
+    zip_path = BUILDS_DIR / f"ZernMC-win-{version}.zip"
+    
+    if not zip_path.exists():
+        raise HTTPException(404, f"ZIP for version {version} not found")
+    
+    return FileResponse(
+        path=zip_path,
+        filename=f"ZernMC-win-{version}.zip",
+        media_type="application/zip"
+    )
+
+
+# ====================== END ЛАУНЧЕР МЕТА ЭНДПОИНТЫ ======================
+
+
 @app.get("/launcher/info")
 async def get_launcher_full_info():
     """Full launcher information with all available files"""