feat: Enhance Marketplace and Skill Management UI with improved error handling and user feedback

- Updated MarketplaceDrawer to include security notes and manual installation hints.
- Refactored SkillDetailDrawer to display default icons for skills.
- Simplified SkillListItem to use default icons for better readability.
- Integrated gateway status checks and warnings in SkillsPage for improved user awareness.
- Enhanced error handling for skill installation and fetching, providing clearer feedback to users.
- Added new translations for error messages and gateway warnings to improve localization support.

build/preinstalled-skills/self-improving-agent/hooks/openclaw/HOOK.md

@@ -0,0 +1,23 @@
+---
+name: self-improvement
+description: "Injects self-improvement reminder during agent bootstrap"
+metadata: {"openclaw":{"emoji":"🧠","events":["agent:bootstrap"]}}
+---
+
+# Self-Improvement Hook
+
+Injects a reminder to evaluate learnings during agent bootstrap.
+
+## What It Does
+
+- Fires on `agent:bootstrap` (before workspace files are injected)
+- Adds a reminder block to check `.learnings/` for relevant entries
+- Prompts the agent to log corrections, errors, and discoveries
+
+## Configuration
+
+No configuration needed. Enable with:
+
+```bash
+openclaw hooks enable self-improvement
+```