chore: Enforce a few house rules via eslint (#2539)

INSTRUCTIONS.md

@@ -9,7 +9,7 @@ Commands: `yarn install`, `yarn run build`, `yarn run test`, `yarn run coverage`
 ## Code Style
 
 - Conventional Commits (used by semantic-release).
-- Comments explain **why**, not what — only when intent isn't obvious from code.
+- Comments explain **why**, not what -- only when intent isn't obvious from code.
 
 ## TypeScript
 
@@ -32,7 +32,7 @@ Commands: `yarn install`, `yarn run build`, `yarn run test`, `yarn run coverage`
 ## Architecture
 
 - Consolidate duplicate logic when adding helpers; don't leave redundant inline expressions.
-- **Naming consistency:** Renames span all layers — schema, types, CSS, localization keys, templates, docs. All schema fields must appear in the documentation table.
+- **Naming consistency:** Renames span all layers -- schema, types, CSS, localization keys, templates, docs. All schema fields must appear in the documentation table.
 - **Separation of concerns:** `components/` renders only; logic in `components-lib/` controllers (using `ReactiveController` where needed).
 - **Manager pattern:** `CardController` orchestrates managers (`ConfigManager`, `HASSManager`, `ViewManager`, etc.). New cross-cutting concerns → new manager.
 - **Module conventions:** `types.ts` for types/schemas, `*-manager.ts` for coordinators, `*-controller.ts` for logic, `utils/` for helpers.
@@ -40,7 +40,7 @@ Commands: `yarn install`, `yarn run build`, `yarn run test`, `yarn run coverage`
 ## Preferences
 
 - Think through UX states and edge cases **before** writing code.
-- No re-exports or pass-through files — import from source directly.
+- No re-exports or pass-through files -- import from source directly.
 - Derive TypeScript types from Zod schemas (`z.infer<typeof schema>`); no parallel interfaces.
 - User-facing schemas: only user-configurable fields. Internal fields go in a derived interface (`interface InternalFoo extends Foo { ... }`).
 - Shared schemas go in `config/schema/common/` from the start.