Summary

Add 5 new methods to Session/AsyncSession for better kernel introspection and agent workflows:

• complete(code, cursor_pos) - Code completions from kernel (discover DataFrame columns, methods, etc.)
• get_queue_state() - See which cell is executing and which are queued
• clear_outputs(cell_id) - Clear cell outputs before re-execution
• run_all_cells() - Batch execute all code cells
• get_history(pattern, n, unique) - Search kernel input history

Also add new types: CompletionItem, CompletionResult, QueueState, HistoryEntry

Remove MCP server from runtimed-py package - MCP tools are now handled by the separate nteract package.

Changes

• crates/runtimed-py/src/output.rs: Add 4 new result types with proper repr methods
• crates/runtimed-py/src/session.rs: Add 5 sync methods following existing patterns
• crates/runtimed-py/src/async_session.rs: Add 5 async methods with future_into_py
• crates/runtimed-py/src/lib.rs: Register new types in module
• python/runtimed/src/runtimed/init.py: Export new types
• python/runtimed/pyproject.toml: Remove mcp and httpx dependencies, remove runtimed-mcp entry point
• python/runtimed/src/runtimed/_mcp_server.py: Deleted
• python/runtimed/tests/test_mcp.py: Deleted

Verification

• All new types accessible from Python
• All new methods present on Session and AsyncSession
• MCP server removed correctly
• Package builds successfully with maturin
• Existing tests pass (except pre-existing test_binary.py failure)
• Rust formatting and clippy checks pass

PR submitted by @rgbkrk's agent, Quill