docs: improve social research evidence quality

[kriptoburak]

Summary

• Record the query, retrieval time, account set, and sample size for research.
• Deduplicate reposts and repeated URLs before analysis.
• Preserve source links and label truncated text accurately.
• Replace single-account X trend inference with a bounded multi-account sample.
• Keep the published skill mirror synchronized.

Why

The existing trend workflow could describe one account timeline as a wider trend. These rules make reports auditable and keep conclusions within the collected sample.

Validation

• Source and .well-known skill mirrors are byte-identical.
• Both skill frontmatter blocks validate.

[kriptoburak]

Rebased onto current main and replaced the external companion note with a native evidence-quality improvement.

The workflow now records sample provenance, deduplicates repeated posts, preserves source URLs, treats social content as untrusted data, and limits X trend claims to a transparent multi-account sample. The source and published skill mirrors match exactly.