create-backchat-themelisted

# Create a Backchat theme Build source-controlled `*.theme.ts` plugins that replace Backchat's complete visual token set and may opt into the small, validated presentation contract. ## Establish context 1. Locate the Backchat package root containing `package.json` with `"name": "backchat"`. 2. Read `PRODUCT.md`, `src/renderer/src/lib/theme-plugin.ts`, `src/renderer/src/themes/THEME_SPEC.md`, and `src/renderer/src/themes/index.ts` completely. 3. Read [references/token-contract.md](references/token-contract.md) completely. 4. Inspect at least one existing theme and the Appearance settings page before choosing values. Preserve unrelated work in a dirty tree. Treat `THEME_TOKEN_NAMES` as the live source of truth. If it differs from this skill's reference or template, follow the code and update the skill resources in the same change. ## Create a plugin 1. Choose a unique lowercase kebab-case id. Use a distinct product name; do not imply endorsement by another editor or vendor. 2. Add an assertion for the new id to `src/renderer/src/lib/theme-plugin.test.ts`, then run that test and confirm it fails because the plugin is absent. 3. Use [assets/theme.template.ts](assets/theme.template.ts) as the structural starting point. Create `src/renderer/src/themes/<id>.theme.ts` with a default export from `defineThemePlugin`. 4. Set `specVersion: THEME_SPEC_VERSION`, set `appearance` to exactly one of `light` or `dark`, and supply intentional values for ev