feat: Import 35+ skills, merge duplicates, add openclaw installer

Major updates:
- Added 35+ new skills from awesome-opencode-skills and antigravity repos
- Merged SEO skills into seo-master
- Merged architecture skills into architecture
- Merged security skills into security-auditor and security-coder
- Merged testing skills into testing-master and testing-patterns
- Merged pentesting skills into pentesting
- Renamed website-creator to thai-frontend-dev
- Replaced skill-creator with github version
- Removed Chutes references (use MiniMax API instead)
- Added install-openclaw-skills.sh for cross-platform installation
- Updated .env.example with MiniMax API credentials

skills/minimax-xlsx/references/fix.md

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+# FIX — Repair Broken Formulas in an Existing xlsx
+
+This is an EDIT task. You MUST preserve all original sheets and data. Never create a new workbook.
+
+## Workflow
+
+```bash
+# Step 1: Identify errors
+python3 SKILL_DIR/scripts/formula_check.py input.xlsx --json
+
+# Step 2: Unpack
+python3 SKILL_DIR/scripts/xlsx_unpack.py input.xlsx /tmp/xlsx_work/
+
+# Step 3: Fix each broken <f> element in the worksheet XML using the Edit tool
+#   (see Error-to-Fix mapping below)
+
+# Step 4: Pack and validate
+python3 SKILL_DIR/scripts/xlsx_pack.py /tmp/xlsx_work/ output.xlsx
+python3 SKILL_DIR/scripts/formula_check.py output.xlsx
+```
+
+## Error-to-Fix Mapping
+
+| Error | Fix Strategy |
+|-------|-------------|
+| `#DIV/0!` | Wrap: `IFERROR(original_formula, "-")` |
+| `#NAME?` | Fix misspelled function (e.g. `SUMM` → `SUM`) |
+| `#REF!` | Reconstruct the broken reference |
+| `#VALUE!` | Fix type mismatch |
+
+For the full list of Excel error types and advanced diagnostics, see `validate.md`.
+
+## Critical Rules
+
+- The output MUST contain the same sheets as the input. Do NOT create a new workbook.
+- Only modify the specific `<f>` elements that are broken — everything else must be untouched.
+- After packing, always run `formula_check.py` to confirm all errors are resolved.