docs(agents): confirm LIMIT_BREAKTHROUGH.md in AGENTS.md (Wave K3)

Wave M landed LIMIT_BREAKTHROUGH.md in this repo. AGENTS.md upgraded
from hedged 'when present' phrasing to confirmed direct link with
✅ status indicator. Idempotent marker @marker: limit-breakthrough-confirmed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: dancinlife

AGENTS.md

@@ -63,10 +63,7 @@ verification policy**: see [`LATTICE_POLICY.md`](LATTICE_POLICY.md)
    by lattice fit. Bound it by what mathematics, physics, and
    engineering actually permit.
 
-**Companion artifact**: `LIMIT_BREAKTHROUGH.md` (when present) lists
-this project's real limits + per-limit breakthrough assessment
-(HARD_WALL / SOFT_WALL / BREAKABLE_WITH_TECH / UNCLEAR). It is the
-project-specific application of `LATTICE_POLICY.md`.
+**Companion artifact** ✅ confirmed present: [`LIMIT_BREAKTHROUGH.md`](LIMIT_BREAKTHROUGH.md) — this project's real limits + per-limit breakthrough assessment (HARD_WALL / SOFT_WALL / BREAKABLE_WITH_TECH / UNCLEAR). Generated by Wave M (2026-05-12) as the project-specific application of [`LATTICE_POLICY.md`](LATTICE_POLICY.md). <!-- @marker: limit-breakthrough-confirmed -->
 
 **Honesty obligation** (raw#10 C3): claims about external entities
 (companies, fabs, accelerators, life systems) must NOT include