Harden workspace recovery and SCM organization

[ZYKJShadow]

Overview

This PR hardens workspace startup recovery and improves the Agent-side Git/SCM experience. It makes corrupted workspace agent storage safer to read, adds an application-level fallback for startup failures, and keeps hidden or grouped workspace/file-list behavior consistent across sessions.

Changes

• Validate and normalize workspace agent project data before merging it into runtime state.
• Quarantine invalid .async/agent.json files instead of repeatedly failing on startup.
• Add an IPC recovery path that backs up and resets the current workspace .async/ directory.
• Add an application error boundary with reload and .async/ backup/reset recovery actions.
• Add persisted folder grouping for Agent Git changed files, including collapsible directory groups and root-level handling.
• Respect hidden workspace entries in the Agent sidebar workspace selector.
• Refresh related styling and localization for the SCM grouping and recovery UI.
• Add tests for workspace agent storage normalization/quarantine behavior and SCM path grouping.

Verification

• npm test -- main-src/workspaceAgentStore.test.ts src/GitScmVirtualLists.test.ts src/app/agentSidebarWorkspaceList.test.ts
• npm run typecheck