feat(notebook): CI(2,2,2) K3 NK cert v2.2 — two β sources, honest train/test

k=4 (126 sections, 31,752 params): h_Lap≈0.08 (×6.4) + h_Jac≈0.19 (×2.7).
k=2 Jac FAILS (h=1.55). η_L² on held-out test set.
Lean: GIFT.Foundations.K3NewtonKantorovich in core v3.4.11.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Brieuc

.gitignore

@@ -97,3 +97,6 @@ core/
 outputs/zeros6
 outputs/zeros6.gz
 outputs/odlyzko_zeros_2M.npy
+
+# Claude Code session data
+.claude/

CHANGELOG.md

@@ -5,6 +5,27 @@ All notable changes to the GIFT framework are documented in this file.
 The format follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [3.3.25] - 2026-04-18
+
+### K3 Newton-Kantorovich Certificate Notebook
+
+CI(2,2,2) ⊂ ℙ⁵ Donaldson k-sweep notebook published (v2.2).
+
+#### Added
+
+**`docs/notebooks/colab_ci222_cap_v2.ipynb`** — CI(2,2,2) K3 NK certification:
+- k-sweep k=2,3,4 (21/56/126 sections, up to 31,752 params)
+- Two independent β sources: graph Laplacian (h≈0.08, ×6.4) and Jacobian pseudoinverse (h≈0.19, ×2.7)
+- k=2 Jacobian FAILS (h=1.55) — demonstrates certificate selectivity
+- Honest train/test split: η_L² on 1,000-point held-out set (overfit ratio ×3.4)
+- Outputs: `ci222_nk_certificate_v2_1.json` + figure
+
+Formal Lean verification: `GIFT.Foundations.K3NewtonKantorovich` in [core v3.4.11](https://github.com/gift-framework/core).
+
+#### Changed
+
+- `README.md`: updated to core v3.4.11 (131 Lean files)
+
 ## [3.3.24] - 2026-03-02
 
 ### NuFIT 6.0 Update & Publication Cleanup

README.md

@@ -65,7 +65,7 @@ All posts on [giftheory.substack.com](https://giftheory.substack.com/).
 | **Precision** | 0.24% mean deviation across 32 well-measured observables (PDG 2024 / NuFIT 6.0) |
 | **Observables** | 92 total (66 with experimental comparison) |
 | **Parameters** | Zero adjustable (all structurally determined) |
-| **Verified** | 130 Lean 4 files, 4 axioms, zero incomplete proofs ([core v3.4.10](https://github.com/gift-framework/core)) |
+| **Verified** | 131 Lean 4 files, 4 axioms, zero incomplete proofs ([core v3.4.11](https://github.com/gift-framework/core)) |
 | **Uniqueness** | #1 out of 3,070,396 configurations tested |
 
 **Dimensional reduction:** E₈×E₈ (496D) → AdS₄ × K₇ (11D) → Standard Model (4D)
@@ -195,7 +195,7 @@ Statistical validation shows (b₂=21, b₃=77) is the unique optimum among 3,07
   author  = {de La Fournière, Brieuc},
   year    = {2026},
   url     = {https://github.com/gift-framework/GIFT},
-  version = {3.4.9}
+  version = {3.4.11}
 }
 ```