feat: add Obsidian CLI API service

- Add Docker image for the official Obsidian desktop app and CLI.

- Start Obsidian headlessly with Xvfb and DBus setup.

- Expose a safe structured HTTP command API without shell execution.

- Add JWT-based vault, path, and command authorization.

- Support single-vault and multi-vault container mounts.

- Add TypeScript SDK helpers for Obsidian CLI commands.

- Add n8n community node package with Obsidian operations.

- Add docs, compose config, tests, and production image workflow.

app/runner.py

@@ -0,0 +1,58 @@
+import asyncio, uuid, time
+from pathlib import Path
+
+from starlette.responses import JSONResponse
+
+from app.config import CLI_BIN
+
+def error(status_code:int, detail:str) -> JSONResponse:
+  return JSONResponse({"detail": detail}, status_code=status_code)
+
+async def execute_command(args:list[str], cwd:Path, stdin:str|None, timeout:float) -> JSONResponse:
+  command_id = str(uuid.uuid4())
+  command = [CLI_BIN, *args]
+  started = time.perf_counter()
+
+  try:
+    process = await asyncio.create_subprocess_exec(
+      *command,
+      cwd=str(cwd),
+      stdin=asyncio.subprocess.PIPE if stdin is not None else None,
+      stdout=asyncio.subprocess.PIPE,
+      stderr=asyncio.subprocess.PIPE,
+    )
+  except FileNotFoundError:
+    return error(500, f"configured CLI binary was not found: {CLI_BIN}")
+
+  try:
+    stdout_b, stderr_b = await asyncio.wait_for(
+      process.communicate(None if stdin is None else stdin.encode()),
+      timeout=timeout,
+    )
+    timed_out = False
+  except asyncio.TimeoutError:
+    process.kill()
+    stdout_b, stderr_b = await process.communicate()
+    timed_out = True
+
+  duration_ms = int((time.perf_counter() - started) * 1000)
+  stdout = stdout_b.decode(errors="replace")
+  stderr = stderr_b.decode(errors="replace")
+  exit_code = process.returncode if process.returncode is not None else -1
+
+  if timed_out:
+    exit_code = 124
+    stderr = (stderr + f"\nCommand timed out after {timeout}s").strip()
+
+  return JSONResponse(
+    {
+      "id": command_id,
+      "command": command,
+      "cwd": str(cwd),
+      "exit_code": exit_code,
+      "stdout": stdout,
+      "stderr": stderr,
+      "duration_ms": duration_ms,
+      "timed_out": timed_out,
+    }
+  )