Skip redundant sync when configs already linked

[donnes]

Summary

Skip import/export work for adapters when configs are already present or correctly symlinked.

Changes

Modified Files

• src/adapters/amp.ts - Skip import/export when already linked
• src/adapters/antigravity.ts - Skip import/export when already linked
• src/adapters/claude.ts - Skip importing/exporting existing files
• src/adapters/clawdbot.ts - Skip import/export when already linked
• src/adapters/codex.ts - Skip import/export when already linked
• src/adapters/cursor.ts - Skip import/export for already-synced files
• src/adapters/dotfiles.ts - Skip import/export for existing or linked dotfiles
• src/adapters/droid.ts - Skip import/export when already linked
• src/adapters/gemini-cli.ts - Skip import/export when already linked
• src/adapters/github-copilot.ts - Skip import/export when already linked
• src/adapters/goose.ts - Skip import/export when already linked
• src/adapters/kilo.ts - Skip import/export when already linked
• src/adapters/kiro-cli.ts - Skip import/export when already linked
• src/adapters/opencode.ts - Skip import/export when already linked
• src/adapters/roo.ts - Skip import/export when already linked
• src/adapters/trae.ts - Skip import/export when already linked
• src/adapters/vscode.ts - Skip import/export for already-synced files
• src/adapters/windsurf.ts - Skip import/export for already-synced files

Features

• Avoid redundant sync work when repos already contain configs or correct symlinks

Technical Details

• Import skips if repo already has the config or the system path is a symlink
• Export skips if an existing symlink already targets the repo path

Testing

• Not run (not requested)

Breaking Changes

None.