feat: add initial skill authoring workspace

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

skills/office-export-xlsx/SKILL.md

@@ -0,0 +1,80 @@
+---
+name: office-export-xlsx
+description: Use when the user wants to export structured table data into a local .xlsx file through the sgClaw Office pipeline.
+version: 0.1.0
+author: sgclaw
+tags:
+  - office
+  - xlsx
+  - export
+---
+
+# Office Export Xlsx
+
+Convert a structured table artifact into a local `.xlsx` file. This skill is Office-only: it does not navigate websites, inspect browser DOM, or collect source data. It consumes already prepared rows and hands them to `openxml_office`.
+
+## When to Use
+
+- The user asks to export collected data as Excel.
+- An upstream skill already produced `sheet_name`, `columns`, and `rows`.
+- The task needs a local workbook path as the final deliverable.
+
+Do not use this skill for:
+
+- browser navigation
+- data collection from live pages
+- free-form spreadsheet editing without a structured table artifact
+
+## Required Input Artifact
+
+The upstream skill must provide this structure:
+
+```json
+{
+  "source": "https://www.zhihu.com/hot",
+  "sheet_name": "知乎热榜",
+  "columns": ["rank", "title", "heat"],
+  "rows": [[1, "标题", "344万"]]
+}
+```
+
+Rules:
+
+- `sheet_name` is the target workbook sheet name.
+- `columns` is the exact output header order.
+- `rows` is the ordered row list to export.
+- Do not invent missing rows.
+- If the artifact is partial, preserve that status in the final result instead of hiding it.
+- If the upstream artifact was blocked by login/verification or another browser-side issue, do not continue export as if the data were complete.
+
+## Tool Contract
+
+- Call `openxml_office` to render the final `.xlsx`.
+- Do not use browser tools in this skill.
+- Do not use `shell` as the main export path.
+- Return the final local `.xlsx` output path after `openxml_office` succeeds.
+
+## Workflow
+
+1. Validate that `sheet_name`, `columns`, and `rows` are present.
+2. Choose the workbook template and output path.
+3. Pass the structured payload to `openxml_office`.
+4. Return the output workbook path plus a short export summary.
+
+Do not:
+
+- recollect browser data from the source page
+- reformat the structured artifact into prose before export
+- continue other browser exploration after the workbook path is available
+
+## References
+
+- Use [export-flow.md](references/export-flow.md) for the exact export sequence.
+- Template assets for this skill belong under `assets/`.
+
+## Common Mistakes
+
+- Mixing browser collection steps into the Office phase.
+- Reformatting the rows into prose before export.
+- Dropping the header order defined by `columns`.
+- Returning success without the generated local file path.