feat(cases): add inline edit and delete actions

[Lint111]

Summary

• Add distinct edit and delete icon actions beside each desktop case-picker option.
• Add separate, touch-sized edit and delete actions to the mobile case picker.
• Reuse the existing case-settings popover and delete-confirmation flow.
• Preserve row selection as a separate action so editing or deleting cannot accidentally launch a case.

Motivation

Case maintenance was available only through the settings window even though users select cases from the quick-start picker throughout normal work. The extra navigation is especially costly on mobile.

Scope

This is the inline case-management slice extracted from #173. It includes the picker behavior, the exact desktop/mobile styles required by the new controls, and focused tests. It does not change case APIs or deletion semantics.

Interaction details

• Desktop actions appear when a row is hovered or contains keyboard focus.
• Mobile keeps the case-selection target at least 44px high and places the two actions at the row edge.
• Delete continues to require the existing user confirmation.

Validation

• npx vitest run --config config/vitest.config.ts test/run-mode-ui.test.ts: 15 passed
• Temporary Playwright probe: 6 mobile action buttons and 2 desktop action buttons visible; all mobile controls remained inside a 390px viewport
• npm run check:frontend-syntax: 26 files passed
• npm run build: passed
• Commit formatting hook: passed
• git diff --check: passed