docs: release v4.6.2 - documentation optimization and /memory:load refinement

### Documentation Optimization

**Optimized `/memory:load` Command Specification**:
- Reduced documentation from 273 to 240 lines (12% reduction)
- Merged redundant sections for better information flow
- Removed unnecessary internal implementation details
- Simplified usage examples while preserving clarity
- Maintained all critical information (parameters, workflow, JSON structure)

### Documentation Updates

**CHANGELOG.md**:
- Added v4.6.2 release entry with documentation improvements

**COMMAND_SPEC.md**:
- Updated `/memory:load` specification to match actual implementation
- Corrected syntax: `[--tool gemini|qwen]` instead of outdated `[--agent] [--json]` flags
- Added agent-driven execution details

**GETTING_STARTED.md**:
- Added "Quick Context Loading for Specific Tasks" section
- Positioned between "Full Project Index Rebuild" and "Incremental Related Module Updates"
- Includes practical examples and use case guidance

**README.md**:
- Updated version badge to v4.6.2
- Updated latest release description

**COMMAND_REFERENCE.md**:
- Added `/memory:load` command reference entry

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

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

GETTING_STARTED.md

@@ -226,6 +226,31 @@ Suitable for large-scale refactoring, architectural changes, or first-time CCW u
 - Weekly routine maintenance
 - When AI output drift is detected
 
+#### Quick Context Loading for Specific Tasks
+
+When you need immediate, task-specific context without updating documentation:
+
+```bash
+# Load context for a specific task into memory
+/memory:load "在当前前端基础上开发用户认证功能"
+
+# Use alternative CLI tool for analysis
+/memory:load --tool qwen "重构支付模块API"
+```
+
+**How It Works**:
+- Delegates to an AI agent for autonomous project analysis
+- Discovers relevant files and extracts task-specific keywords
+- Uses CLI tools (Gemini/Qwen) for deep analysis to save tokens
+- Returns a structured "Core Content Pack" loaded into memory
+- Provides context for subsequent agent operations
+
+**When to Use**:
+- Before starting a new feature or task
+- When you need quick context without full documentation rebuild
+- For task-specific architectural or pattern discovery
+- As preparation for agent-based development workflows
+
 #### Incremental Related Module Updates
 
 Suitable for daily development, updating only modules affected by changes: