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-performance/SKILL.md

@@ -0,0 +1,54 @@
+---
+name: cc-rule-performance
+description: Performance Optimization
+author: affaan-m
+version: "1.0"
+---
+
+# Performance Optimization
+
+## Model Selection Strategy
+
+**Haiku 4.5** (90% of Sonnet capability, 3x cost savings):
+- Lightweight agents with frequent invocation
+- Pair programming and code generation
+- Worker agents in multi-agent systems
+
+**Sonnet 4.5** (Best coding model):
+- Main development work
+- Orchestrating multi-agent workflows
+- Complex coding tasks
+
+**Opus 4.5** (Deepest reasoning):
+- Complex architectural decisions
+- Maximum reasoning requirements
+- Research and analysis tasks
+
+## Context Window Management
+
+Avoid last 20% of context window for:
+- Large-scale refactoring
+- Feature implementation spanning multiple files
+- Debugging complex interactions
+
+Lower context sensitivity tasks:
+- Single-file edits
+- Independent utility creation
+- Documentation updates
+- Simple bug fixes
+
+## Ultrathink + Plan Mode
+
+For complex tasks requiring deep reasoning:
+1. Use `ultrathink` for enhanced thinking
+2. Enable **Plan Mode** for structured approach
+3. "Rev the engine" with multiple critique rounds
+4. Use split role sub-agents for diverse analysis
+
+## Build Troubleshooting
+
+If build fails:
+1. Use **build-error-resolver** agent
+2. Analyze error messages
+3. Fix incrementally
+4. Verify after each fix