Surgically rebase metacommand changes onto main

[nhorton]

This commit adds a meta-command system to DeepWork that provides:

1. Meta-commands: Job-level entry points (e.g., /job_name) that route user intent to the appropriate step
2. Hidden step commands: Step commands now use uw. prefix by default to indicate they are internal/hidden from the main command list
3. Exposed steps: Steps can opt into visibility with exposed: true
4. Quality criteria: Declarative quality criteria on steps rendered with standard evaluation framing in stop hooks

Key changes:

• Added exposed and quality_criteria fields to Step schema/parser
• Added get_meta_command_filename() and updated get_step_command_filename() with exposed parameter in adapters
• Added generate_meta_command() and updated generate_all_commands() in generator to create meta-commands first, then hidden step commands
• Added new meta-command templates for Claude and Gemini
• Updated step templates to support quality_criteria
• Updated deepwork_jobs standard job to use exposed: true on learn step and declarative quality_criteria instead of hooks
• Added exposed_step_job test fixture
• Updated all tests to account for new file naming scheme

Generated files updated via deepwork install.