chore(skills): sync .gemini and .github skills and fix i18n validator

.github/skills/gh-issue-scheduler/SKILL.md

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+---
+name: gh-issue-scheduler
+description: Finds all open GitHub issues that haven't been replied to by the owner, summarizes them, and generates a solution plan. Use when the user wants to audit pending tasks or plan maintenance work.
+---
+
+# Gh Issue Scheduler
+
+## Overview
+
+The `gh-issue-scheduler` skill helps maintainers track community feedback by identifying unaddressed issues and drafting actionable technical plans to resolve them.
+
+## Workflow
+
+1.  **Identify Unanswered Issues**: Run the bundled script to fetch issues without owner replies.
+    *   Command: `bash scripts/find_unanswered.sh`
+2.  **Analyze and Summarize**: For each identified issue, summarize the core problem and the user's intent.
+3.  **Generate Solution Plans**: Draft a technical "Action Plan" for each issue, including:
+    *   **Root Cause Analysis** (if possible)
+    *   **Proposed Fix/Implementation**
+    *   **Verification Strategy**
+4.  **Present to User**: Display a structured report of all pending issues and their respective plans.
+
+## Tool Integration
+
+### Find Unanswered Issues
+```bash
+bash scripts/find_unanswered.sh
+```
+
+## Report Format
+
+When presenting the summary, use the following Markdown structure:
+
+### 📋 Unanswered Issues Audit
+
+#### Issue #[Number]: [Title]
+- **Author**: @username
+- **Summary**: Concise description of the problem.
+- **Action Plan**:
+    1. Step 1 (e.g., Investigate file X)
+    2. Step 2 (e.g., Apply fix Y)
+    3. Verification (e.g., Run test Z)