feat: add global/local scope option to Mode Writer mode

[roomote]

This PR implements the feature requested in #5972 to add a global/local scope option to the Mode Writer mode.

Changes Made

1. Updated Mode Writer permissions: Modified the fileRegex in .roomodes from (\.roomodes$|\.roo/.*\.xml$|\.yaml$) to (\.roomodes$|.*\.xml$|.*\.yaml$) to allow the Mode Writer to access global YAML files outside the project directory.

2. Added scope selection step: Modified the Mode Writer workflow to ask users upfront whether they want to create a global mode (available in all projects) or a local mode (project-specific).

3. Updated workflow with scope-aware paths:

   • Global modes: Write to the system's custom_modes.yaml file
   • Local modes: Write to the project's .roomodes file
   • Rules directories follow the same pattern

4. Created comprehensive path guidance: Added a new instruction file (7_global_mode_paths.xml) that provides detailed guidance on constructing the correct paths for global mode creation across different operating systems.

Testing

• ✅ All existing CustomModesManager tests pass
• ✅ All linting checks pass
• ✅ All type checks pass

Acceptance Criteria Met

✅ When creating a global mode, the configuration is written to the global custom_modes.yaml file
✅ When creating a local mode, the configuration is written to the project's .roomodes file
✅ The Mode Writer prompts for scope selection before proceeding
✅ File paths are correctly handled based on the selected scope

Fixes #5972

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Important

Adds global/local scope option to Mode Writer mode, updating permissions, workflow, and path handling for mode configurations.

• Behavior:
  • Adds global/local scope option to Mode Writer mode, prompting users to choose scope before mode creation.
  • Global modes are written to custom_modes.yaml in the system's global settings directory.
  • Local modes are written to the project's .roomodes file.
• Permissions:
  • Updates fileRegex in .roomodes to allow Mode Writer to access global YAML files.
• Workflow:
  • Updates 1_mode_creation_workflow.xml to include scope selection and path handling based on scope.
  • Adds 7_global_mode_paths.xml for guidance on global mode path construction across OS.
• Testing:
  • Confirms all existing tests, linting, and type checks pass.

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[daniel-lxs]

Closing, see #5973 (comment)