fix: address PR review feedback and separate from productivity commands

- Remove productivity commands (belong in separate PR github#1170)
- Translate Korean testimonial to English
- Fix Black line length to default (88)
- Use full file paths in instructions (specs/[feature]/...)
- Remove NEW_COMMANDS_SUMMARY.md (wrong PR)

Addresses review comments from PR github#1172

Author: Baek, JH

KENT_BECK_TDD_INTEGRATION.md

@@ -402,7 +402,7 @@ Commands for implementing Kent Beck's Test-Driven Development methodology:
 
 ## 💬 User Testimonial
 
-> "Kent Beck의 TDD 블로그를 읽고 spec-kit에 적용해봤는데, 정말 효과적이었습니다. AI가 반복 코드를 만들거나 테스트를 약화시키는 것을 자동으로 감지해주니까, 코드 품질이 확 올라갔어요. Spec-Kit의 빠른 문서화와 Kent Beck의 엄격한 TDD를 결합하니까 정말 최고의 조합이더라구요!"
+> "After reading Kent Beck's TDD blog, I integrated it with spec-kit and found it incredibly effective. The automatic detection of AI warning signs—like repetitive code generation and test weakening—significantly improved code quality. Combining Spec-Kit's rapid documentation with Kent Beck's disciplined TDD creates a powerful development workflow."
 >
 > — JH Baek, Software Developer
 

NEW_COMMANDS_SUMMARY.md

@@ -247,15 +247,6 @@ Additional commands for enhanced quality and validation:
 | `/speckit.analyze`   | Cross-artifact consistency & coverage analysis (run after `/speckit.tasks`, before `/speckit.implement`) |
 | `/speckit.checklist` | Generate custom quality checklists that validate requirements completeness, clarity, and consistency (like "unit tests for English") |
 
-#### Productivity & Optimization Commands
-
-Commands for managing development environment and conversation efficiency:
-
-| Command                     | Description                                                           |
-|-----------------------------|-----------------------------------------------------------------------|
-| `/rec_remove_agents_mcp`    | Analyze current project and recommend which agents/MCP servers to keep or remove for optimal context management |
-| `/compact_with_topic`       | Automatically analyze recent conversation topics and run `/compact` with intelligent focus |
-
 #### Kent Beck TDD Integration Commands
 
 Commands for implementing [Kent Beck's Test-Driven Development](https://tidyfirst.substack.com/p/augmented-coding-beyond-the-vibes) methodology within spec-kit: