feat(theme): register native V2 opencode theme - #49846

What

Register packages/tui/src/theme/assets/v2/opencode.json as the built-in opencode theme and remove the hard-coded DEFAULT_THEME from @opencode/theme.

full TUI opencode → native V2 asset
Mini fallback     → native V2 asset
invalid theme     → native V2 opencode fallback

The old V1 assets/opencode.json remains available as a migration fixture but is no longer used by production fallback paths.

Native asset

The V2 asset is generated from the current V1 OpenCode theme and then minimized:

• base: complete shared semantic token structure and @dialog
• light: complete light hue palette
• dark: complete dark hue palette plus only semantic values that differ from base

Light and dark resolve token-for-token identically to the migrated V1 source.

Remove DEFAULT_THEME

• Delete the 452-line hard-coded theme in packages/theme/src/tui/defaults.ts.
• Remove the public DEFAULT_THEME export.
• Move DEFAULT_CATEGORICAL into the independent categorical.ts module; V1 migration still uses it when no semantic hues can be inferred.
• Expose getOpenCodeTheme(), which lazily decodes and caches the native asset; use it in the registry, Mini, and tests.
• Use a migrated V1 fixture in @opencode/theme tests, preserving package dependency direction.
• Decode and cache the built-in V2 asset only when getOpenCodeTheme() is first called.

Verification

• Native V2 light = migrated V1 light, token-for-token.
• Native V2 dark = migrated V1 dark, token-for-token.
• packages/theme: typecheck; 6 tests pass.
• packages/tui: typecheck; 101 focused theme/Mini tests pass.
• Registration visual comparison before the DEFAULT_THEME cleanup: 40/40 states identical across opencode-light, opencode-dark, catppuccin-light, and dracula-dark.

Remove text.status

The native migration exposed that text.status was a session-tab-specific namespace. Remove it from partial/complete schemas, resolved types, V1 migration, and the native asset. Consumers now use explicit hues at the requested step:

• running → hue.accent[800]
• permission/question/activity unread → hue.interactive[800]
• error unread → text.feedback.error.base (unchanged)