chore(release): Bump version to 1.1.1 with security and dependency up…

[justindobbs]

…dates

• Bump version from 1.1.0 to 1.1.1 in pyproject.toml and webui app.py
• Update CHANGELOG.md with 1.1.1 release notes documenting pydantic-ai>=1.66.0 SSRF fix requirement, openai-agents>=0.10.4 update, and shell=False security enhancement in maintainer subprocess calls

Summary

• What problem does this PR solve?
• How does it solve it (major bullets)?

Testing

• python -m pytest
• python -m ruff check agent_bench
• Additional targeted tests (list):

Checklist

• Spec/docs updated (README, SPEC_FREEZE, changelog, etc., as needed)
• New tasks/tests added to registry + SPEC if applicable
• Roadmap items tracked in appropriate boards (if applicable)
• Security/privacy review (if touching telemetry, signing, or bundles)
• Verified CI status once pushed