Fix feedback panel contrast

[mattheliu]

What changed

• replace the translucent feedback entry with a solid deep-teal primary button
• render the feedback panel as an opaque high-contrast dark card
• give verdict, category, close, back, progress, and completion controls solid surfaces
• give the final send action a distinct high-contrast treatment
• add component assertions that the main choices and confirm action are never transparent
• bump the public package to 0.4.4

Why

The previous theme-dependent colors could resolve to a translucent panel and white text on white controls in the DSH dark theme. The feedback flow was technically present but visually unreadable.

Impact

The full flow is now readable independently of the host light/dark theme while keeping the same single-button interaction and privacy behavior.

Verification

• pnpm test:all
• 26 client/unit tests passed
• 10 backend tests passed
• server build passed
• real DSH 0.1.0-rc.6 plugin E2E passed
• visually verified both the verdict picker and send-before-preview state in the local DSH dark theme