✨ feat(cockpit): retire legacy session shell

[zrr1999]

Summary

• Make workspace-scoped session routes canonical and turn legacy /sessions and /sessions/:sessionId pages into compatibility redirects.
• Move session loaders/actions into route-neutral server modules and remove the legacy session shell ownership.
• Preserve distinct Cockpit/workspace access authorization while sharing LoginPage, TokenManagementSurface, and navigation styling across shells.
• Extract the daemon-event-to-timeline converter and reduce event/timeline normalization duplication and complexity.

Routes and auth

• Canonical: /(workbench)/[workspaceId]/sessions and /(workbench)/[workspaceId]/sessions/[sessionId].
• Legacy URLs remain bookmark-compatible through redirects to workspace-scoped canonical URLs.
• Cockpit authentication and workspace access remain distinct; canonical workspace route checks are retained.

Verification

• Added real Playwright navigation coverage for legacy login/session URLs and canonical final URLs.
• Cockpit browser script now runs both the component browser suite and the real E2E suite.
• Commit hooks passed: architecture ratchets, dependency boundaries, terminology checks, formatting/lint checks, and commit validation.
• git diff --check and staged diff checks passed.

Quality gates and warnings

• pnpm install --frozen-lockfile passed.
• pnpm --filter @zendev-lab/spark-cockpit exec svelte-kit sync passed.
• pnpm exec jscpd --version, pnpm exec vp --version, and Cockpit Playwright resolution passed.
• Full package/browser/typecheck/jscpd/hygiene gates are expected to run in CI; no full suite was claimed in this publishing step.