feat: converge Vera around Matter workspaces

[shawliu998]

Summary

• Rebase the desktop product around Matter workspaces while keeping legacy project surfaces disabled by default.
• Add versioned Matter foundations and explicit classification migration, with inference gated until the planned release stage.
• Add Matter landing, profile, workspace navigation, packaged restart coverage, and CSP redirect coverage.

Validation

• Backend build, P0, P1, and Matter convergence suites passed.
• Frontend P0, production build, i18n, and desktop CSP runtime v2 passed.
• Security review reported no P0/P1 findings.

Release-gate status

The full packaged macOS Gate1 cross-restart suite remains pending. The prior canonical run passed its source layers and stopped at a stale CSP assertion that expected /projects to return 200; commit a697527a updates that contract for the new /projects → /matters redirect, and the targeted CSP suite now passes. The complete packaged run was not restarted because the exclusive Keychain window was released to another task.

This PR merges the implementation for integration only. It does not mark packaged Gate1 complete; the roadmap and evidence files intentionally retain that pending status.