Add explicit permissions to GitHub Actions workflows

Add GITHUB_TOKEN permissions blocks to workflows following
security best practices (principle of least privilege):

- ci.yaml: Add 'contents: read' (only needs to checkout code)
- test.yml: Add 'contents: read' (only needs to checkout code)
- sync-wiki.yml: Add 'contents: write' (needs to push to wiki)

Existing workflows already have permissions:
- draft-release.yml: 'contents: write' (creates releases)
- release-electron.yml: 'contents: write' (creates releases)

This addresses GitHub security warnings about workflows
not limiting GITHUB_TOKEN permissions.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: MarkoVcode

.github/workflows/ci.yaml

@@ -5,6 +5,9 @@ on:
     branches: ["**"]
   pull_request:
 
+permissions:
+  contents: read  # Required to checkout code
+
 jobs:
   test:
     runs-on: ubuntu-latest

.github/workflows/sync-wiki.yml

@@ -8,6 +8,9 @@ on:
       - 'docs/**/*.md'
   workflow_dispatch:  # Allow manual trigger
 
+permissions:
+  contents: write  # Required to checkout code and push to wiki
+
 jobs:
   sync-wiki:
     runs-on: ubuntu-latest

.github/workflows/test.yml

@@ -6,6 +6,9 @@ on:
   pull_request:
     branches: [ main, develop ]
 
+permissions:
+  contents: read  # Required to checkout code
+
 jobs:
   test-frontend:
     runs-on: ubuntu-latest