FileGRC 0.18.7

Fix repeated retention-review graph construction and Markdown parsing during public workflow and Program readiness assessments. Intermediate results are shared within each invocation, then discarded so later calls observe current records and content. Concurrent assessments remain isolated; verified browser snapshot caches retain their existing validation.

On a 462-record workspace, measured Node 24 workflow assessment time fell from 39.04 seconds to 1.42 seconds, with byte-for-byte identical assessment output. Complete loading, validation, and assessment fell from 42.33 seconds to 4.47 seconds.

This is a backward-compatible patch in the 0.18.x line. Model v13 and workflow contract 1 remain unchanged; no record migration is required. Coordinated filegrc and create-filegrc packages are version 0.18.7.

Validation: complete Node 24 suite, supported-platform CI, two independent code/security reviews, package checks, zero audit vulnerabilities, fresh consumer validation, and browser checks.