feat(agentic): add tictactoe web ui

[xsuler]

Summary

• Add a cartoon Tic-Tac-Toe web UI backed by an OpenAI-compatible tool-call model.
• Support keyboard/click moves and switching first player.
• Clarify Tic-Tac-Toe prompts so digits are treated as empty square labels.

Closes #104

Tests

• ruff check examples/agentic/tictactoe/game.py examples/agentic/tictactoe/run_agent.py examples/agentic/tictactoe/run_agent_no_tool.py examples/agentic/tictactoe/web_ui.py
• python -m py_compile examples/agentic/tictactoe/game.py examples/agentic/tictactoe/run_agent.py examples/agentic/tictactoe/run_agent_no_tool.py examples/agentic/tictactoe/web_ui.py

[gemini-code-assist]

Code Review

This pull request introduces a cartoon web UI (web_ui.py) for playing Tic-Tac-Toe against an OpenAI-compatible model, along with prompt refinements in game.py, run_agent.py, and run_agent_no_tool.py to clarify game rules for the agent. The review feedback highlights three key areas for improvement: adding thread synchronization to TicTacToeServer to prevent race conditions on shared state, robustly handling potential exceptions during JSON request parsing in _read_json, and using direct attribute access on the OpenAI SDK response instead of converting it to a dictionary.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[adohe]

/lgtm