Keep Flyde imports working after file moves

[nexiumbiz-debug]

/claim #112

Summary

• Register a VS Code onDidRenameFiles handler for Flyde projects.
• Rewrite local source.type: file references in .flyde files when an imported .flyde, .flyde.ts, or .flyde.js file moves.
• Handle both single-file moves and folder moves, including nested inline visual nodes.
• Add focused regression coverage for file and folder move path updates.

Demo

Before the fix, a flow that imported ./components/child.flyde would keep that stale path after the imported file was moved, so the import stopped resolving.

After the fix, the VS Code rename handler updates the importing .flyde file during the move. The focused regression covers this scenario:

flows/main.flyde imports ./components/child.flyde
rename ./components/child.flyde -> ./shared/child.flyde
main.flyde source path is rewritten to ./shared/child.flyde

The same path-rewrite logic also covers folder moves, including nested inline visual nodes.

Verification

• corepack pnpm --filter flyde-vscode compile
• ./vscode/node_modules/.bin/mocha.CMD --ui tdd ./vscode/out/test/flyde-file-renames.test.js
• git diff --check

Transparency note: implementation prepared with AI-assisted coding and verified with the commands above.