Allow users to set custom system prompts

[mrubens]

Important

Allow users to set custom system prompts by creating a file in the workspace, with UI support and tests included.

• Behavior:
  • Users can override system prompts by creating a file at .roo/system-prompt-[mode].
  • If the file exists, its content is used as the system prompt, excluding role definition and custom instructions.
  • If the file does not exist, default prompts are used.
• Functions:
  • loadSystemPromptFile() in custom-system-prompt.ts reads the custom prompt file.
  • getSystemPromptFilePath() in custom-system-prompt.ts constructs the file path for the custom prompt.
• UI:
  • PromptsView.tsx updated to include a disclosure for overriding system prompts.
  • Button added to open or create the custom prompt file.
• Tests:
  • Added tests in custom-system-prompt.test.ts to verify custom prompt loading behavior.
  • Added tests in fs.test.ts for safeReadFile() and fileExistsAtPath() functions.
• Misc:
  • safeReadFile() moved to fs.ts for reuse.

^{This description was created by for 8ab92b55ab0ffc77199deb25bfd6f4f1c19d4da8. It will automatically update as commits are pushed.}

[changeset-bot]

⚠️ No Changeset found

Latest commit: 1f0211e

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[ellipsis-dev]

This function is identical to the existing safeReadFile. Consider importing and reusing the existing function instead.

• function safeReadFile (custom-instructions.ts)

[ellipsis-dev]

Document and consider refactoring the branch where a file-based custom system prompt exists. This branch omits default sections (TOOL USE, CAPABILITIES, MODES) – ensure that this behavior is intentional and clearly documented.