feat(cli): add -s/--silent flag to suppress non-essential output

[sfedyakov]

Summary

Add global -s/--silent CLI parameter to enable silent mode for all agents (claude, gemini, codemie-code).

When enabled, suppresses:

• Welcome ASCII art and messages
• Version warning prompts
• Update available prompts
• Shutdown messages
• Goodbye messages

Implementation Details

Approach: Setter Method on Adapter (Option 3)

Why this approach:

• ✅ Explicit, type-safe API via public setSilentMode(boolean) method
• ✅ No breaking changes to existing code
• ✅ Backward compatible with plugins that have static silentMode: true in metadata
• ✅ Metadata mutation controlled through well-defined public method

Changes

1. src/agents/core/AgentCLI.ts:

   • Added -s, --silent CLI option (line 60)
   • Call setSilentMode(true) when flag is present (lines 126-132)
   • Added 'silent' to configOnlyOptions to prevent passing to agent executables (line 342)

2. src/agents/core/BaseAgentAdapter.ts:

   • Made metadata mutable by cloning in constructor: this.metadata = { ...metadata }
   • Added public setSilentMode(enabled: boolean) method

3. src/agents/core/__tests__/BaseAgentAdapter.test.ts (NEW):

   • 4 unit tests for setSilentMode() functionality
   • Tests verify: enable/disable, original metadata unchanged (cloning), shallow copy

Test Results

✅ All tests passing: 1414 tests across 64 test files
✅ Build successful: No TypeScript compilation errors
✅ New tests: 4 tests added for BaseAgentAdapter

Usage

# Enable silent mode (long form)
codemie-claude --silent

# Enable silent mode (short form)
codemie-gemini -s

# Works with all agents
codemie-code -s --task "hello"

Backward Compatibility

• ✅ Existing plugins with silentMode: true in metadata continue to work
• ✅ No breaking API changes
• ✅ All existing tests pass
• ✅ Flag is consumed by CodeMie CLI and NOT passed to agent executables

Test plan

• Build project successfully
• All unit tests pass (1414/1414)
• Help text shows -s, --silent option
• Flag does not get passed to underlying agent executable
• setSilentMode() correctly mutates metadata
• Original metadata unchanged (cloning verified)