chore: move completed CLI Exclusion Filters epic to Completed directory

Reorganized epic plans after successful v7.0.0 release implementation:

Changes:
- Moved CLI_Exclusion_Filters epic from backlog/ to Completed/
  - All 4 features and 9 story files
  - Epic delivered 111 tests (370% of requirements)
  - All acceptance criteria met and validated

- Removed obsolete planning documents:
  - teach-ai epic (duplicate - already in Completed/)
  - ORGANIZATION_SUMMARY.md (no longer needed post-merge)
  - TECHNICAL_DEBT_filesystem_vector_store.md (debt resolved in v7.0.0)

This epic included:
- Language exclusion (--exclude-language flag)
- Path exclusion (--exclude-path flag with glob patterns)
- Combined filter logic with conflict detection
- Comprehensive documentation with 26 common patterns

Status: Fully implemented, tested, documented, and released in v7.0.0

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: jsbattig