ci: declare workflow-level contents: read on the 9 python-N.yml build workflows

Pins the default GITHUB_TOKEN to contents: read on the per-Python-
version build workflows. Each runs sphinx-build against the translated
rst files and uploads the rendered HTML as a workflow artifact, with
no GitHub API mutation.

Motivation: CVE-2025-30066 (March 2025 tj-actions/changed-files
compromise) exfiltrated GITHUB_TOKEN from workflow logs. Per-workflow
caps bound runtime authority irrespective of repo or org default,
give drift protection if the default ever widens, and are credited
per-file by the OpenSSF Scorecard Token-Permissions check.

YAML validated locally with yaml.safe_load.

Signed-off-by: Arpit Jain <arpitjain099@gmail.com>

Author: arpitjain099

.github/workflows/python-310.yml

@@ -5,6 +5,9 @@ on:
   schedule:
     - cron: '15 0 * * *'
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-311.yml

@@ -5,6 +5,9 @@ on:
   schedule:
     - cron: '0 0 * * *'
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-312.yml

@@ -5,6 +5,9 @@ on:
   schedule:
     - cron: '45 23 * * *'
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-313.yml

@@ -13,6 +13,9 @@ on:
       - main
       - '3.13'
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-314.yml

@@ -13,6 +13,9 @@ on:
       - main
       - '3.14'
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-315.yml

@@ -13,6 +13,9 @@ on:
       - main
       - '3.15'
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-37.yml

@@ -3,6 +3,9 @@ name: python-37
 on:
   workflow_dispatch:
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-38.yml

@@ -3,6 +3,9 @@ name: python-38
 on:
   workflow_dispatch:
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml

.github/workflows/python-39.yml

@@ -3,6 +3,9 @@ name: python-39
 on:
   workflow_dispatch:
 
+permissions:
+  contents: read
+
 jobs:
   sync:
     uses: ./.github/workflows/sync.yml