v0.1.18: queryEcho leak fix, capped-list disclosure in text output

queryEcho leak fix, capped-list disclosure in text output

Added:

• openlibrary_get_work gains an optional notice output field (enrichment block) disclosing when text output caps a long subject list.

Fixed:

• openlibrary_search_books rendered a literal **queryEcho:** undefined in the text trailer for a bare or single-filter query — both ctx.enrich({ queryEcho }) call sites now guard on queryEcho !== undefined. (#10)
• openlibrary_search_books rendered every Internet Archive identifier per work in text output, undisclosed — format() now caps at 5 per work, with the omitted count disclosed via the enrichment trailer; structuredContent is unchanged. (#11)
• openlibrary_get_work and openlibrary_search_authors silently truncated subjects/top_subjects in text output (caps of 10 and 5) with no disclosure — both now emit an enrichment notice naming the omitted count; structuredContent already carried the complete arrays. (#13)

210 tests pass; bun run devcheck clean.

CHANGELOG v0.1.18