feat: import 35 skills from affaan-m/everything-claude-code

- Add 9 agent skills (cc-agent-*)
- Add 10 command skills (cc-cmd-*)
- Add 8 skill files (cc-skill-*)
- Add 8 rule skills (cc-rule-*)
- Update README.md skill count from 225 to 260
- Add new skills to Full Skill Registry
- Add credit to affaan-m in Credits section
- Regenerate skills_index.json

Source: https://github.com/affaan-m/everything-claude-code
Author attribution: affaan-m, version 1.0

skills/cc-rule-coding-style/SKILL.md

@@ -0,0 +1,77 @@
+---
+name: cc-rule-coding-style
+description: Coding Style
+author: affaan-m
+version: "1.0"
+---
+
+# Coding Style
+
+## Immutability (CRITICAL)
+
+ALWAYS create new objects, NEVER mutate:
+
+```javascript
+// WRONG: Mutation
+function updateUser(user, name) {
+  user.name = name  // MUTATION!
+  return user
+}
+
+// CORRECT: Immutability
+function updateUser(user, name) {
+  return {
+    ...user,
+    name
+  }
+}
+```
+
+## File Organization
+
+MANY SMALL FILES > FEW LARGE FILES:
+- High cohesion, low coupling
+- 200-400 lines typical, 800 max
+- Extract utilities from large components
+- Organize by feature/domain, not by type
+
+## Error Handling
+
+ALWAYS handle errors comprehensively:
+
+```typescript
+try {
+  const result = await riskyOperation()
+  return result
+} catch (error) {
+  console.error('Operation failed:', error)
+  throw new Error('Detailed user-friendly message')
+}
+```
+
+## Input Validation
+
+ALWAYS validate user input:
+
+```typescript
+import { z } from 'zod'
+
+const schema = z.object({
+  email: z.string().email(),
+  age: z.number().int().min(0).max(150)
+})
+
+const validated = schema.parse(input)
+```
+
+## Code Quality Checklist
+
+Before marking work complete:
+- [ ] Code is readable and well-named
+- [ ] Functions are small (<50 lines)
+- [ ] Files are focused (<800 lines)
+- [ ] No deep nesting (>4 levels)
+- [ ] Proper error handling
+- [ ] No console.log statements
+- [ ] No hardcoded values
+- [ ] No mutation (immutable patterns used)