Private-call E2E tests against the 148 promises (Memo 152 E-08)

[a6b8]

Freeze the five private-schema promises as an end-to-end suite so a future refactor cannot break them silently (the CLI split already showed "byte-identical" does not hold).

Suite: tests/integration/private-call-e2e.test.mjs (9 cases), mapping:

1. The private path scans BEFORE import() — a forbidden-pattern fixture is rejected and never imported (marker stays undefined).
2. A clean executeRequest schema (reference style) runs via private call.
3. A private fixture appears in NEITHER list NOR search NOR the serve tool source (resolveAllSchemas).
4. The trusted path still loads geo/inkar-style schemas (real top-level imports) scan-free, while the SAME file is rejected on the private path.
5. An unresolvable requiredLibrary fails loud with LIB-001 (no silent allowlist fallback).
6. H-12 building block: a private fixture WITH a markdown resource validates via the v4 MainValidator.

New fixtures: trusted-src/providers/trusted-import-schema.mjs (geo/inkar analogue) and markdown-schema.mjs. No source changes. Full suite green (718).