Refine desktop workspace layout and dock chrome

[IchenDEV]

Outcome

Refines the desktop workspace into a quieter, more consistent layout: rounded floating panels share a lighter shadow and even spacing; compact window-strip controls replace repeated navigation; the right dock tabs and close button sit in the title strip. The project entry is subdued, icon-only buttons are circular, and an empty Files panel no longer shows a redundant document row.

Change record

• Change: docs/sdlc/changes/2026-09-28-codex-layout-reset/intent.md
• Specification: docs/sdlc/changes/2026-09-28-codex-layout-reset/spec.md
• Verification: docs/sdlc/changes/2026-09-28-codex-layout-reset/verification.md

Review and release

• Acceptance evidence covers the current diff, including rendered light, dark and narrow states and a fresh post-merge render.
• Required local checks passed: 110 targeted desktop tests, renderer build, documentation, scope, diff and ready-PR Gate checks.
• Merge authorization: pending
• Release authorization: not requested

Remote CI and native window behavior remain separate from the local browser-renderer evidence.