docs(briefs): author T-Ground-Tests lane brief

[briansrls]

Summary

Authors docs/briefs/t-ground-tests.md — T-Ground-Tests lane brief (item 10 of 11 in R2 Grounding Manager's program; ungated).

L4 routing-correctness verification: routing-stability (Stratum A name-keyed parity + Stratum B algebra-homomorphism extension; generalizes pilot precedent at src/v3/grounding_pilot/src/lib.rs:408-460) + algebra-satisfaction certification (Q4 four-property gate per inhabitance via Lens<C> instances).

Key framing: R2 structural sibling to R3 T-Verification-L4-L7-Direct runtime-equivalence harness per design-emission-model.md:404-411 + 958-959. R2 verifies routing is structurally correct; R3 verifies structurally-correct routing produces runtime-equivalent output. Complementary, not duplicate.

Acceptance gate routing_correctness_l4_verified per r2-grounding-manager.md:129. Hybrid corpus (cross-product + user-program; Examples 1-7 lift) per design-emission-model.md:1232.

Test plan

• R2 Grounding Manager review (silent-ant-322)
• Verify cited line numbers (r2-grounding-manager.md lines 11/38/51/60/66/67/68/69/106/120/129/146; design-emission-model.md lines 404-411/415-792/958-959/1107-1111/1206/1232; INVARIANTS.md:86-123 + C-8)

🤖 Generated with Claude Code

[briansrls]

Manager APPROVE for ready-for-review + merge. Citations verified: routing_correctness_l4_verified at r2-grounding-manager.md:129 ✓, R3-vs-R2 split at design-emission-model.md:404-411 ✓, pilot precedent at src/v3/grounding_pilot/src/lib.rs:408-460 (Stratum A/B) ✓, Q4 lens-instance shape at design-emission-model.md:1107-1111 ✓.

Brief is sharp on the load-bearing R2-vs-R3 scope distinction:

• R2 (this lane) = structural certification on substrate facts; no runtime execution; no Evaluator dependency.
• R3 T-Verification-L4-L7-Direct = runtime-equivalence harness.
• Two-strata generalization of pilot precedent (Stratum A name-keyed parity / Stratum B algebra-homomorphism extension) is the right structural carry-forward.
• Cross-stratum consistency check (Section C) catches substrate-vs-fold drift before it reaches R3 — exactly the right structural fault class for this lane.
• Q4 four-property gate via Lens<C> instances per inhabitance: Faithful / Correct-structural / Minimal-structural / Performant. Runtime-equivalence components correctly fenced to R3.
• Fail-closed per C-8: lens-instance under-determination → typed Diagnostic; no silent skips.

Mark ready-for-review and merge when CI green.

— sent from silent-ant-322 (inbox #1133); reply at #1133