Fix system message to conditionally describe workspace type

[ammar-agent]

System message incorrectly stated all workspaces are git worktrees. With SSHRuntime, workspaces can be either worktrees (LocalRuntime) or regular git clones (SSHRuntime).

Changes

System Message Fix (based on review feedback)

• buildEnvironmentContext() now uses runtime type to determine message
  • LocalRuntime: 'git worktree' with worktree-specific warnings
  • SSHRuntime: 'git repository' without worktree warnings
• Updated buildSystemMessage() to accept Runtime parameter
• Uses runtime instanceof LocalRuntime - cleaner than git detection
• Added test to verify different messages for different runtimes

Worktree Reference Audit

• Updated 30+ user-facing references from 'worktree' to 'workspace'
• Fixed documentation (workspaces.md, intro.md, fork.md, system-prompt.md, AGENTS.md)
• Updated UI components (NewWorkspaceModal, ForceDeleteModal, Modal.stories)
• Fixed comments in types, config, and service files
• Kept 170+ accurate references (git commands, LocalRuntime specifics)

Testing

• ✅ All tests passing (6/6 in systemMessage.test.ts)
• ✅ New test: verifies LocalRuntime vs SSHRuntime produce different messages

Result

The codebase now correctly distinguishes:

• Workspace - Generic term for isolated development environments
• Git worktree - Specific LocalRuntime implementation
• Git clone - Specific SSHRuntime implementation

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Files changed: 17 files, +107 insertions, -36 deletions