refactor(projman): extract skills and consolidate commands

Major refactoring of projman plugin architecture:

Skills Extraction (17 new files):
- Extracted reusable knowledge from commands and agents into skills/
- branch-security, dependency-management, git-workflow, input-detection
- issue-conventions, lessons-learned, mcp-tools-reference, planning-workflow
- progress-tracking, repo-validation, review-checklist, runaway-detection
- setup-workflows, sprint-approval, task-sizing, test-standards, wiki-conventions

Command Consolidation (17 → 12 commands):
- /setup: consolidates initial-setup, project-init, project-sync (--full/--quick/--sync)
- /debug: consolidates debug-report, debug-review (report/review modes)
- /test: consolidates test-check, test-gen (run/gen modes)
- /sprint-status: absorbs sprint-diagram via --diagram flag

Architecture Cleanup:
- Remove plugin-level mcp-servers/ symlinks (6 plugins)
- Remove plugin README.md files (12 files, ~2000 lines)
- Update all documentation to reflect new command structure
- Fix documentation drift in CONFIGURATION.md, COMMANDS-CHEATSHEET.md

Commands are now thin dispatchers (~20-50 lines) that reference skills.
Agents reference skills for domain knowledge instead of inline content.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plugins/projman/commands/clear-cache.md

@@ -4,7 +4,9 @@ description: Clear plugin cache to force fresh configuration reload after market
 
 # Clear Cache
 
-Clear plugin cache to force fresh configuration reload. Run this after marketplace updates.
+## Purpose
+
+Clear plugin cache to force fresh configuration reload after marketplace updates.
 
 ## When to Use
 
@@ -12,17 +14,21 @@ Clear plugin cache to force fresh configuration reload. Run this after marketpla
 - When MCP servers show stale configuration
 - When plugin changes don't take effect
 
-## What It Does
+## Workflow
 
-1. Clears `~/.claude/plugins/cache/leo-claude-mktplace/`
-2. Forces Claude Code to re-read `.mcp.json` files on next session
-
-## Instructions
-
-Run this command, then **restart your Claude Code session** for changes to take effect.
+Execute cache clear:
 
 ```bash
 rm -rf ~/.claude/plugins/cache/leo-claude-mktplace/
 ```
 
-After clearing, inform the user: "Cache cleared. Restart Claude Code for changes to take effect."
+Then inform user: "Cache cleared. Restart Claude Code for changes to take effect."
+
+## Visual Output
+
+```
+╔══════════════════════════════════════════════════════════════════╗
+║  📋 PROJMAN                                                      ║
+║  Clear Cache                                                     ║
+╚══════════════════════════════════════════════════════════════════╝
+```