feat: copy transcript to Obsidian vault on open

Config: obsidian.vault path. On Obsidian button click, file is copied to
vault dir then opened via obsidian:// URI. Vault path configurable in settings.

api/router.py

@@ -216,7 +216,15 @@ async def open_file(body: dict, user: dict = Depends(current_user)):
     mode = body.get("mode", "editor")  # "editor" | "folder" | "obsidian"
     if mode == "obsidian":
         from urllib.parse import quote
-        subprocess.Popen(["xdg-open", f"obsidian://open?path={quote(path, safe='/')}"])
+        cfg = load_config()
+        vault = cfg.get("obsidian", {}).get("vault", "").strip()
+        if vault and os.path.isdir(vault):
+            dest = os.path.join(vault, os.path.basename(path))
+            shutil.copy2(path, dest)
+            target = dest
+        else:
+            target = path
+        subprocess.Popen(["xdg-open", f"obsidian://open?path={quote(target, safe='/')}"])
     elif mode == "folder" and shutil.which("dolphin"):
         subprocess.Popen(["dolphin", "--select", path])
     elif mode == "folder":