Clarify CSV escaping and spreadsheet text import

[manuelconcari-ai]

The CSV instructions say to wrap values in quotes but do not specify escaping embedded quotes. For example, wrapping the single value normal",=1+1,"rest without escaping creates three cells. CSV quotes also do not prevent spreadsheet formula interpretation.

Specify doubled embedded quotes, preserved commas and line breaks, and records aligned with the header. Keep source text intact after the existing label/date/null formatting. Append one conditional line to the save confirmation recommending text import, with no guarantee for automatic opening or save/reopen.

This changes only the export skill's CSV section and its save confirmation. Prerequisites, mode selection, file naming, the saving workflow, the four existing confirmation lines, the Output Rules and the Markdown template remain unchanged.

One pre-existing inconsistency is worth noting without changing it here: mode: public omits author in JSON and the per-report Author field in the Markdown template, while the Markdown table of contents and this CSV header list an Author column with no mode exception. This patch does not change which fields any mode exports.

Validation: the patch applies and reverses at main 60d8813 and composes with the export-permission change in PR #22. A standard-library fixture preserves 28 synthetic values across the actual eleven-column header; a separate control shows naive wrapping splitting one value into three cells. The prepared file matches the documented patch byte for byte. No model-generated export, spreadsheet evaluation or mode filtering was tested.