2x Faster CLI Startup & Smarter Project Detection

#1523 fc1a79f Thanks @Crunchyman-ralph! - Codex cli Validate reasoning effort against model capabilities
- Add provider-level reasoning effort validation for OpenAI models
- Automatically cap unsupported effort levels (e.g., 'xhigh' on gpt-5.1 and gpt-5 becomes 'high')
#1549 98087ac Thanks @Crunchyman-ralph! - Improve CLI startup speed by 2x
#1545 a0007a3 Thanks @Crunchyman-ralph! - Smarter project root detection with boundary markers
- Prevents Task Master from incorrectly detecting .taskmaster folders in your home directory when working inside a different project
- Now stops at project boundaries (.git, package.json, lock files) instead of searching all the way up to the filesystem root
- Adds support for monorepo markers (lerna.json, nx.json, turbo.json) and additional lock files (bun.lockb, deno.lock)
#1523 fc1a79f Thanks @Crunchyman-ralph! - Improve json schemas for ai-related commands making it more compatible with openai models
#1542 b817d6f Thanks @mdimitrovg! - Fixed vertex-ai authentication when using service account and vertex location env variable.

CLI startup speed improved by 2x, smarter project root detection with boundary markers for monorepos, and reasoning effort validation for OpenAI models.