Polish desktop visual hierarchy and multi-tab chrome

[agentfleets]

Summary

• standardize and declutter Author and Read multi-tab chrome
• tighten the Read header and align workbench control geometry
• replace the cyan/indigo visual language with restrained ChatGPT-like graphite neutrals
• strengthen pane hierarchy across all workbenches with distinct canvas, navigation, and inspector tones
• add Retina hairline separators and restrained soft-glass chrome for rails, headers, tab strips, controls, and overlays
• keep editors, documents, tables, PDFs, and terminal content opaque for clarity

Verification

• npm run build
• bash scripts/lint-desktop-tokens.sh
• node --test src/ui/*.test.ts (81 passed)
• packaged, ad-hoc signed, signature-verified, launched, and visually inspected as TermiPod Visual Review.app on macOS

Review build

• product name: TermiPod Visual Review
• bundle id: app.termipod.desktop.visualreview
• version: 2026.730.1242

[agentfleets]

Closing for now at the operator’s request. The visual-polish branch remains active while the remaining UI issues are fixed; a complete PR will be opened after final review.