fix: guard against undefined currentProject in sidebar decoration provider

[wahajahmed010]

Description

Fixes a crash in the sidebar decoration provider when Container.currentProject is undefined.

Root cause: Container._currentProject is declared but never initialized, so it remains undefined whenever no saved project matches the currently open folder (e.g. a window opened on a folder not in the Project Manager list, or during startup before the current project is resolved). The provideFileDecoration method in decoration.ts accessed .rootPath on Container.currentProject without a null guard, throwing:

TypeError: Cannot read properties of undefined (reading 'rootPath')

Because provideFileDecoration is invoked repeatedly (once per tree item), the errors flood the Extension Host and can cause it to terminate.

Fix: Added a truthiness check for Container.currentProject before accessing .rootPath.

Changes

• src/sidebar/decoration.ts: Guard Container.currentProject with a null check before accessing .rootPath

Testing

• Compiles without new errors (pre-existing type errors in other files are unrelated)
• Logic verified: when currentProject is undefined, the function returns undefined (no decoration), which is the correct fallback behavior

Closes #938

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This contribution was created with assistance from an AI coding agent (Buck/OpenClaw). The fix was reviewed and validated for correctness.