fix(ppt): align mode action with Standard mode

[SuperstructureJH]

Summary

• collapse the hero Agent Preset picker wrapper to its visible control width
• place the PPT mode action directly beside Standard mode
• align the PPT action with the row's borderless default, hover, selected, pressed, and focus states
• add regression coverage for the layout and interaction-style contract

Root cause

The Agent Preset picker's generic 360 px minimum width remained active in the hero workspace row. The PPT action was structurally adjacent but visually pushed to the right edge of that reserved area.

Verification

• npm ci
• npm test -- test/kimi-ppt-integration.test.ts — 9/9 tests
• npm run typecheck
• npm test — 701/701 tests across 84 files
• npm run package:dev:mac:arm64
• exact packaged-app native UI: adjacent default layout, selected tint, template-gallery expansion, and toggle back to Standard mode

Acceptance boundary

Deployment and colleague-device acceptance remain separate follow-up gates.