feat: add per-agent loop safeguards for tool-call turns

Introduce three optional per-agent config fields to bound tool-call loop
execution: `max_iterations` (default 15), `streaming_timeout` (default
120s), and `turn_timeout` (default 300s wall-clock).

- Plumb limits from agent config through `_build_agents_table` and
  `_start_agent` into `MultimodalAgentMCPServer` via `request_limits`
- Apply `max_iterations` and `streaming_timeout` to `RequestParams`
- Wrap turn dispatch in `asyncio.wait_for` to enforce `turn_timeout`,
  logging a warning on timeout
- Document the new fields in README

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "pallas-mcp"
-version = "0.2.2"
+version = "0.3.0"
 description = "FastAgent MCP Bridge — generic runtime for serving FastAgent agents over StreamableHTTP"
 requires-python = ">=3.13.5"
 dependencies = [