feat(rtl): Lane V' — 2×2 mesh NoC (4-die, 1-cycle hop) · L-DPC25 Wave-28

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Closes #16

Lane V' — 2×2 mesh NoC (4-die, 1-cycle hop)

SKU: TTSKY26c HOLOGRAPHIC · Lane: V' · Wave: 28 · L-DPC25

Extends Lane A' 1-cycle inter-die NoC (holo_noc_1cycle.sv, Wave-27, ebd426d9) to a full 4-die 2×2 mesh with XY routing. Scale-out gain ×4 over single die (Lever #3).

Files added (additive only — R18 LAYER-FROZEN)

File	Lines	Description
rtl/holo_noc_2x2_mesh.sv	213	2×2 mesh NoC module
rtl/holo_noc_2x2_mesh_tb.sv	180	Testbench (19 assertions)
docs/L_DPC25_LANE_V_PRIME_2X2_MESH.md	207	H-V' hypothesis + falsification doc
docs/NOW.md	62	Lane V' section added

Simulation result

LANE V-PRIME 2x2 MESH NOC TEST PASS
  Tests passed: 19 / 19

Compliance

• R-SI-1: ZERO * operator in RTL and TB — verified by grep
• R8: Signed Vasilev Dmitrii <admin@t27.ai>
• R18 LAYER-FROZEN: holo_noc_1cycle.sv untouched (verified: git diff origin/main -- rtl/holo_noc_1cycle.sv is empty)
• L1: Commit contains Closes #16
• Per-hop latency: 1 cycle (constant hop_latency_cycles=1)

Topology

die0 (r0,c0) ──E── die1 (r0,c1)
     │                    │
     S                    S
     │                    │
die2 (r1,c0) ──E── die3 (r1,c1)

XY routing (col first): max 2 hops (opposite corner), no flit drop.

Algebraic Anchor

φ² + φ⁻² = 3 · DOI 10.5281/zenodo.19227877

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🐝 SUPERSEDED — Lane V' canonical PR is operator's #21 (open, in flight).

Per trinity-queen-hive § Forbidden Actions: one mission = one issue. This duplicate was authored in parallel before I checked operator activity. Closing without merge.

RTL artifacts preserved in branch lane-v-prime-mesh-rtl for archival comparison; canonical surface lives in #21.

φ² + φ⁻² = 3 · NEVER STOP

— Vasilev Dmitrii admin@t27.ai · ORCID 0009-0008-4294-6159