fix: Fix 2 critical CLI issues blocking production (Kimi QA)

**Critical Issues Fixed:**

Issue #1: CLI Commands Were BROKEN ⚠️ CRITICAL
- Problem: 4 CLI commands existed but failed at runtime with ImportError
- Root Cause: Modules had example_usage() instead of main() functions
- Impact: Users couldn't use quality, stream, update, multilang features

**Fixed Files:**
- src/skill_seekers/cli/quality_metrics.py
  - Renamed example_usage() → main()
  - Added argparse with --report, --output flags
  - Proper exit codes and error handling

- src/skill_seekers/cli/streaming_ingest.py
  - Renamed example_usage() → main()
  - Added argparse with --chunk-size, --batch-size, --checkpoint flags
  - Supports both file and directory inputs

- src/skill_seekers/cli/incremental_updater.py
  - Renamed example_usage() → main()
  - Added argparse with --check-changes, --generate-package, --apply-update flags
  - Proper error handling and exit codes

- src/skill_seekers/cli/multilang_support.py
  - Renamed example_usage() → main()
  - Added argparse with --detect, --report, --export flags
  - Loads skill documents from directory

Issue #2: Haystack Missing from Package Choices ⚠️ CRITICAL
- Problem: Haystack adaptor worked but couldn't be used via CLI
- Root Cause: package_skill.py missing "haystack" in --target choices
- Impact: Users got "invalid choice" error when packaging for Haystack

**Fixed:**
- src/skill_seekers/cli/package_skill.py:188
  - Added "haystack" to --target choices list
  - Now matches main.py choices (all 11 platforms)

**Verification:**
✅ All 4 CLI commands now work:
   $ skill-seekers quality --help
   $ skill-seekers stream --help
   $ skill-seekers update --help
   $ skill-seekers multilang --help

✅ Haystack now available:
   $ skill-seekers package output/skill --target haystack

✅ All 164 adaptor tests still passing
✅ No regressions detected

**Credits:**
- Issues identified by: Kimi QA Review
- Fixes implemented by: Claude Sonnet 4.5

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

src/skill_seekers/cli/package_skill.py

@@ -185,7 +185,7 @@ Examples:
 
     parser.add_argument(
         "--target",
-        choices=["claude", "gemini", "openai", "markdown", "langchain", "llama-index", "weaviate", "chroma", "faiss", "qdrant"],
+        choices=["claude", "gemini", "openai", "markdown", "langchain", "llama-index", "haystack", "weaviate", "chroma", "faiss", "qdrant"],
         default="claude",
         help="Target LLM platform (default: claude)",
     )