feat: add skip reasons to Discord notifications

API Changes:
- Track skip reason along with package name
- Changed skippedPackages from string[] to Array<{name, reason}>
- Reasons: "package not found", "missing tpmjs field", "invalid tpmjs field"

Workflow Changes:
- Format skipped packages as "package-name - reason"
- Display one package per line in Discord notification

Example Discord output:
📋 Skipped Packages
@scope/package-1 - missing tpmjs field
package-2 - invalid tpmjs field

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

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

.github/workflows/sync-keyword.yml

@@ -59,7 +59,7 @@ jobs:
 
           # Store skipped packages for Discord
           if [ "$skipped" -gt 0 ]; then
-            skippedList=$(echo "$response" | jq -r '.data.skippedPackages[]?' 2>/dev/null | paste -sd ", " - || echo "")
+            skippedList=$(echo "$response" | jq -r '.data.skippedPackages[]? | "\(.name) - \(.reason)"' 2>/dev/null | paste -sd "\n" - || echo "")
             if [ -n "$skippedList" ]; then
               echo "$skippedList" > /tmp/skipped_packages.txt
             fi