Modernize task and workflow documentation architecture

Based on Gemini CLI analysis, updated all command documentation to align with current Single Source of Truth (SSoT) architecture.

## Key Updates

### Command Reference Modernization
- Updated all `/task:context` and `/workflow:context` references to unified `/context` command
- Removed all references to deprecated `/task:sync` and `/workflow:sync` commands
- Updated related commands sections across all task and workflow files

### Architecture Alignment
- Clarified JSON-first data model where `.task/*.json` files are authoritative
- Updated descriptions to reflect that markdown files are generated views, not synchronized documents
- Removed outdated "bidirectional sync" concepts in favor of automatic data consistency

### File Reference Standardization
- Fixed `TODO_CHECKLIST.md` → `TODO_LIST.md` naming inconsistencies
- Updated workflow integration examples to use proper command names
- Standardized command integration descriptions

### Documentation Consistency
- Aligned task creation, breakdown, execution, and replanning documentation with current architecture
- Updated workflow issue integration to reflect JSON-based task creation
- Enhanced CHANGELOG.md with comprehensive documentation modernization details

## Impact
- Eliminates confusion about deprecated commands
- Provides accurate guidance on current system behavior
- Aligns documentation with actual implementation
- Reduces maintenance overhead by removing outdated synchronization concepts

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

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

.claude/commands/task/breakdown.md

@@ -436,7 +436,7 @@ Post-breakdown validation:
 After breakdown:
 - `/task:execute` - Run subtasks using JSON task context
 - `/task:status` - View hierarchy from JSON files and TODO_LIST.md
-- `/task:context` - Analyze task relationships and JSON structure
+- `/context` - Analyze task relationships and JSON structure
 - `/task:replan` - Adjust breakdown and update task structure
 
 ## Examples

.claude/commands/task/create.md

@@ -397,8 +397,7 @@ Created 3 tasks:
 After creation, use:
 - `/task:breakdown` - Split into hierarchical subtasks with JSON files
 - `/task:execute` - Run the task with summary generation
-- `/task:context` - View task details and file references
-- `/task:sync` - Validate file consistency across system
+- `/context` - View task details, status and relationships
 
 ## Examples
 

.claude/commands/task/replan.md

@@ -460,7 +460,7 @@ Apply? (y/n): y
 ## Related Commands
 
 - `/task:breakdown` - Initial task breakdown with JSON file creation
-- `/task:context` - Analyze current state from file system
+- `/context` - Analyze current state from file system
 - `/task:execute` - Execute replanned tasks with new structure
-- `/task:sync` - Validate file consistency after replanning
+- `/context` - View updated task structure and relationships
 - `/workflow:replan` - Replan entire workflow with session updates