app: core-measurement — the measurement-schema.md document model

Pure Kotlin/JVM, faithful to the schema contract: two-clock (wall RFC3339 +
*_mono_ns), units in field names, observation/interpretation split
(tests[] vs findings[]), columnar train evidence (nulls preserved per
index), the full v1 test-type registry, the anonymization logical types as
field notes, and a finding-requires-evidence invariant.

The one piece with real logic — §7.3 deterministic verdict derivation
(category = worst finding light; >50% failed/unsupported → inconclusive;
overall = worst category, inconclusive only if all are) — is implemented
in Verdicts and fully unit-tested. Document JSON round-trips (snake_case
wire names, null-in-columns), typed builders for train/traceroute/resolver
evidence.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

echolot-app/settings.gradle.kts

@@ -22,3 +22,4 @@ rootProject.name = "echolot-app"
 // can run integration tests against a live server. Android modules
 // (core-probe, core-shizuku, app) join as they land.
 include(":core-protocol")
+include(":core-measurement")