feat(hub-guide): language-agnostic auto-trigger across all skills

- Add principle 27: 'Language-Agnostic Auto-Trigger' to engineering-principles
- Remove hardcoded English-only keyword lists from all 26 skill descriptions
- Replace with concept-based detection: triggers from code context, project files,
  and file types regardless of spoken language
- Update detect-project.sh hook output with language-agnostic message

skills/typescript/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: typescript
-description: TypeScript best practices — strict mode, type patterns, generics, module system, async patterns, and project organization. Use when writing TypeScript code, configuring tsconfig, or whenever the user mentions "TypeScript," "TS," "ESM," "deno," "bun," "type annotation," "generics," "interface," "type," "strict mode," or "tsconfig."
+description: TypeScript best practices — strict mode, type patterns, generics, module system, async patterns, and project organization. Use when writing TypeScript code, configuring tsconfig. Triggers when working with this language's files, regardless of spoken language."
 ---
 
 # TypeScript Best Practices