Add artifact flow arrows to TEST STAGE and remove empty line from SVG

Co-authored-by: leofang <5534781+leofang@users.noreply.github.com>

Author: Copilot

CONTRIBUTING.md

@@ -106,7 +106,7 @@ flowchart TD
         T1 --- T2
     end
 
-    %% Build Stage
+    %% Build Stage  
     subgraph BUILD["🔨 BUILD STAGE"]
         subgraph BUILD_PLATFORMS["Parallel Platform Builds"]
             B1["linux-64<br/>(Self-hosted)"]
@@ -156,8 +156,10 @@ flowchart TD
 
     %% Artifact Flow Arrows (Cache Reuse)
     GITHUB_CACHE -.->|"mini CTK reuse"| BUILD
+    GITHUB_CACHE -.->|"mini CTK reuse"| TEST
 
     %% Artifact Flow Arrows (Wheel Fetch)
+    GITHUB_ARTIFACTS -.->|"wheel fetch"| TEST
     GITHUB_ARTIFACTS -.->|"wheel fetch"| RELEASE
 
     %% Styling

ci/.ci-pipeline-regen.md

@@ -53,6 +53,8 @@ This file contains the prompt and requirements for regenerating `ci-pipeline.svg
 - Additional artifact flow arrows (dashed, orange #FF9800):
   - From GitHub Cache (mini CTK) back to Build Stage with "mini CTK reuse" label
   - From GitHub Artifacts (wheels) to Release Pipeline with "wheel fetch" label
+  - **NEW**: From GitHub Cache (mini CTK) to Test Stage with "mini CTK reuse" label
+  - **NEW**: From GitHub Artifacts (wheels) to Test Stage with "wheel fetch" label
 - Arrow marker definition with hand-drawn style (orange arrow heads, not black)
 - Use stroke-dasharray="5,3" for artifact flow arrows