feat: implement missing ddx patterns command

[mehdipiraee]

Summary

The README documents ddx patterns commands that don't exist in the CLI implementation, causing user confusion and broken workflows.

Problem

The README clearly documents these commands under "Resource Commands":

ddx patterns list          # List available patterns
ddx patterns apply <name>  # Apply pattern to project

However, running these commands results in:

$ ddx patterns --help
Error: unknown command "patterns" for "ddx"

Documentation vs Implementation Gap

README Claims:

• ddx patterns list - List available patterns ❌
• ddx patterns apply <name> - Apply pattern to project ❌

CLI Actually Has:

• ddx list - Lists all resources (templates, patterns, prompts, etc.) ✅
• ddx apply <name> - Apply any resource ✅

Root Cause Analysis

Looking at the codebase:

• ✅ ddx prompts command IS implemented (prompts.go, factory functions, registration)
• ❌ ddx templates command is NOT implemented (tracked in feat: implement missing ddx templates command #22)
• ❌ ddx patterns command is NOT implemented (no patterns.go, no factory functions)

Only the prompts resource command was actually built - templates and patterns were documented but never implemented.

Expected Implementation

Following the same pattern as ddx prompts:

1. Create cli/cmd/patterns.go with:

   func runPatternsList(cmd *cobra.Command, args []string) error
   func runPatternsShow(cmd *cobra.Command, args []string) error

2. Add factory functions in cli/cmd/command_factory_commands.go:

   func (f *CommandFactory) newPatternsListCommand() *cobra.Command
   func (f *CommandFactory) newPatternsShowCommand() *cobra.Command

3. Register commands in cli/cmd/command_factory.go:

   patternsCmd := &cobra.Command{
       Use:     "patterns",
       Short:   "Manage code patterns",
       Aliases: []string{"pattern"},
   }
   patternsCmd.AddCommand(f.newPatternsListCommand())
   patternsCmd.AddCommand(f.newPatternsShowCommand())
   rootCmd.AddCommand(patternsCmd)

User Impact

Current Workaround:
Users must use generic commands:

• ddx list (shows all resources mixed together)
• ddx apply pattern-name

With Implementation:
Users can use documented, intuitive commands:

• ddx patterns list (shows only code patterns)
• ddx patterns show <name> (display pattern content)

Use Cases for Patterns

Code patterns are reusable solutions for common programming tasks:

• Error handling patterns
• Authentication patterns
• Database connection patterns
• API response patterns
• Testing patterns
• Logging patterns

Having dedicated commands makes these much more discoverable and usable.

Acceptance Criteria

• ddx patterns --help shows help text
• ddx patterns list lists available patterns from library/patterns/
• ddx patterns list --search <term> filters patterns
• ddx patterns show <name> displays pattern content
• Commands follow same pattern as ddx prompts
• Error handling for missing patterns directory
• Proper test coverage

Related Issues

This is part of a broader documentation-implementation gap:

• Missing ddx templates command (feat: implement missing ddx templates command #22)
• README needs to be aligned with actual CLI capabilities

🤖 Generated with Claude Code