QA regression: SynthesisService behavior tests fail against app-behaviour implemented flows

[meharajM]

Summary

npm run validate:regression fails with 5 test failures in src/modules/SynthesisEngine/__tests__/SynthesisService.test.ts.

These failures are in behavior paths marked Implemented in ContextEngine/app-behaviour.md (LiteRT readiness/fallback/single-pass topic path).

Environment

• Date: 2026-06-01
• Repo: meharajM/context.md
• Command: cd ContextEngine && npm run validate:regression

Observed failures

1. uses raw Inbox fallback when the LiteRT-LM model is missing

• Expected readiness to include missingModels
• Received readiness missing that field

2. uses the bundled demo model when the downloaded model is missing

• Expected available: true, status: ready, demo fallback detail
• Received available: false, status: unavailable, LiteRT synthesis is disabled in settings.

3. uses LiteRT-LM output when the native runtime is available

• Expected readiness ready
• Received unavailable

4. uses the selected topic in a single synthesis pass when one is provided

• Expected native synth call count 1
• Received 0

5. falls back to raw Inbox and marks LiteRT not ready after native synthesis rejects

• Expected readiness ready
• Received unavailable

Why this matters

These failures block confidence in implemented behavior around:

• Manual capture fallback guarantees
• LiteRT availability/fallback semantics
• Topic-directed single-pass synthesis

Suggested fix direction

• Align SynthesisService readiness semantics with current runtime settings behavior.
• Ensure tests initialize runtime settings deterministically (LiteRT enabled/disabled path).
• Re-verify one-pass selected-topic synth path and readiness state transitions.

Acceptance criteria

• npm run validate:regression passes.
• All 5 failing tests in SynthesisService.test.ts pass with deterministic setup.