fix(workspaces): persist durable workspace identity

[YoruSamaOG]

Summary

Workspace grouping now stays stable when chats move between local, branch, and worktree contexts. A chat that moves into a concrete worktree gets its own durable workspace identity instead of relabeling sibling chats that still belong to the original branch.

The desktop sandbox also starts reliably enough to verify the workspace layout end-to-end: dev launches sanitize stale environment state, register the dev protocol correctly, tolerate broken stdout/stderr pipes, and allow the dev app origin through server CORS.

Details

Area	Outcome
Durable workspace projection	Threads now link to persisted workspace rows with stable WorkspaceIds and workspace metadata in snapshots.
Branch/worktree movement	Same-worktree branch label changes preserve workspace identity, while branch/local-to-worktree moves create a new workspace identity for only the moved chat.
Existing dev data	Migration 34 rebuilds projection workspace rows from each thread's actual branch/worktree fields to repair bad workspace labels.
Sidebar behavior	The sidebar prefers persisted workspace metadata when available and falls back to legacy thread metadata for older snapshots.
Desktop sandbox	dev:sandbox avoids stale launcher/env state and no longer crashes on broken pipe logging during local verification.

Validation

• pnpm exec vp test apps/server/src/orchestration/Layers/ProjectionPipeline.test.ts apps/server/src/orchestration/projector.test.ts apps/web/src/components/ChatView.logic.test.ts apps/web/src/components/Sidebar.logic.test.ts
• pnpm exec vp run typecheck
• pnpm exec vp check
• Ran dev:sandbox with Node 24 and verified migration 34_RebuildProjectionWorkspaces repaired the sandbox DB: old feat/enhancements chats remained under feat/enhancements, while the moved chat stayed under t3code/handle-greeting.

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