Remove GIT_SSL_NO_VERIFY, fix root cause with DinD MTU=1340

The TLS handshake failure was caused by MTU mismatch (pod: 1340,
DinD bridge: 1500), not certificate verification.

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

.gitea/workflows/ci.yaml

@@ -6,9 +6,6 @@ on:
   pull_request:
     branches: [main]
 
-env:
-  GIT_SSL_NO_VERIFY: "true"
-
 jobs:
   lint-and-test:
     runs-on: ubuntu-22.04

.gitea/workflows/dvc-data-update.yaml

@@ -7,9 +7,6 @@ on:
       - "dvc.yaml"
       - "dvc.lock"
 
-env:
-  GIT_SSL_NO_VERIFY: "true"
-
 jobs:
   validate-data:
     runs-on: ubuntu-latest

.gitea/workflows/train.yaml

@@ -8,9 +8,6 @@ on:
       - "configs/**"
       - "dvc.yaml"
 
-env:
-  GIT_SSL_NO_VERIFY: "true"
-
 jobs:
   train:
     runs-on: ubuntu-latest

gitea-runner/deployment.yaml

@@ -20,8 +20,6 @@ data:
       file: .runner
       capacity: 1
       timeout: 3h
-      envs:
-        GIT_SSL_NO_VERIFY: "true"
       labels:
         - "ubuntu-latest:docker://catthehacker/ubuntu:act-22.04"
         - "ubuntu-22.04:docker://catthehacker/ubuntu:act-22.04"
@@ -87,6 +85,8 @@ spec:
               mountPath: /certs
         - name: docker-in-docker
           image: docker:dind
+          args:
+            - --mtu=1340
           securityContext:
             privileged: true
           env: