feat(desktop): add project task kanban board

[contentscoin]

Summary

• add a List / Board layout switch to project Tasks
• render all six task statuses as stable kanban columns, including empty columns
• open the existing task detail, activity, comments, and related-channel context from each card

Verification

• pnpm typecheck
• pnpm check
• pnpm test (5,799 passed)
• pnpm build:e2e
• Playwright smoke: project tasks can switch to a kanban board and open task activity (1 passed)

[github-actions]

🔐 Codex Security Review

Status: review required for the current range.

The current range is eed74bde2f4797714335ac10c56c0b0244c1def4...c8aef2619d24860a038e8fd78af41f2c2cf039f7.
A new review must complete for this exact range. When manual authorization
is required, a Block organization member must comment exactly
@buzz-security-review c8aef2619d24860a038e8fd78af41f2c2cf039f7 to authorize a new review.
Any previous review applies only to its recorded range.