docs: Update all documentation for v2.1.0 release

Updates across all major documentation files to reflect v2.1.0 release
status and recent completions.

Changes:
- CLAUDE.md:
  * Updated version from v2.0.0 to v2.1.0
  * Updated date to November 29, 2025
  * Updated test count from 391 to 427
  * Moved completed PRs (#195, #198) and Issue #203 to "Completed" section
  * Updated "Next Up" priorities

- README.md:
  * Updated version badge from 2.0.0 to 2.1.0
  * Updated test badge from 379 to 427 passing

- CHANGELOG.md:
  * Added Issue #203 (Configurable EXCLUDED_DIRS) to Unreleased section
  * Documented 19 comprehensive tests for exclude_dirs feature
  * Listed both extend and replace modes

- FUTURE_RELEASES.md:
  * Marked v2.1.0 as "Released" (November 29, 2025)
  * Moved "Fix 12 unified tests" to completed
  * Updated release schedule table

- FLEXIBLE_ROADMAP.md:
  * Updated current status from v1.0.0 to v2.1.0
  * Added latest release date
  * Expanded "What Works" section with new features
  * Updated test count to 427

All documentation now accurately reflects:
- v2.1.0 release status ✅
- 427 tests passing (up from 391) ✅  - Issue #203 completion ✅
- PR #195 and #198 merged status ✅

Related: #203

README.md

@@ -2,11 +2,11 @@
 
 # Skill Seeker
 
-[![Version](https://img.shields.io/badge/version-2.0.0-blue.svg)](https://github.com/yusufkaraaslan/Skill_Seekers/releases/tag/v2.0.0)
+[![Version](https://img.shields.io/badge/version-2.1.0-blue.svg)](https://github.com/yusufkaraaslan/Skill_Seekers/releases/tag/v2.1.0)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 [![Python 3.10+](https://img.shields.io/badge/python-3.10+-blue.svg)](https://www.python.org/downloads/)
 [![MCP Integration](https://img.shields.io/badge/MCP-Integrated-blue.svg)](https://modelcontextprotocol.io)
-[![Tested](https://img.shields.io/badge/Tests-379%20Passing-brightgreen.svg)](tests/)
+[![Tested](https://img.shields.io/badge/Tests-427%20Passing-brightgreen.svg)](tests/)
 [![Project Board](https://img.shields.io/badge/Project-Board-purple.svg)](https://github.com/users/yusufkaraaslan/projects/2)
 [![PyPI version](https://badge.fury.io/py/skill-seekers.svg)](https://pypi.org/project/skill-seekers/)
 [![PyPI - Downloads](https://img.shields.io/pypi/dm/skill-seekers.svg)](https://pypi.org/project/skill-seekers/)