What problem does it solve? Start9 maintains eight Angular + Taiga UI web frontends (StartOS ui/setup-wizard, StartWRT, StartTunnel, brochure-marketplace, start9-store, ops-server, support-server) whose codebases are mid-migration, so copying neighboring code often reproduces patterns that review will rewrite. This Skill supplies the canonical doctrine, recipes, antipattern catalog, and verified Taiga 5 API reference so new code matches the fleet's target style on the first pass. ## Core Features & Use Cases - House-style doctrine and review checklist: Codifies rules for standalone components, signal-based APIs, inline templates, DI patterns, i18n, and styling, plus a greppable antipattern list for code review. - On-demand reference files: Fourteen references cover bootstrapping, components, styling, DI, state, forms, overlays, routing, conventions, shared libraries, antipatterns, Taiga 5 APIs, recipes, and per-repo deltas. - Verified Taiga 5 quick reference: Documents v4-to-v5 renames, dead APIs, and need-to-primitive lookup tables to prevent hallucinated Taiga APIs. - Use Case: When asked to add a dialog with a validated form to the StartOS UI, consult the recipes, forms, and overlays references to produce a selectorless component using NonNullableFormBuilder, tui-textfield composition, and TuiResponsiveDialogService that passes review without rewrites. ## Quick Start Use the start9-frontend skill to write a new routed page with a form for the StartOS web UI following house style.