release: v0.3.1 configuration operations

[shenjiecode]

v0.3.1

Publishes the configuration operations improvements delivered by #52:

• one GitHub save-and-test action with four explained non-destructive sub-results
• classic PAT PR/Issue capability verified from explicit OAuth scopes
• automatic commit testing off by default with a minutes-based interval (minimum 5 minutes)
• one overall Test all connectivity action with per-check status and problem messages
• versioned YAML configuration export/import with strict validation, atomic import, and no Secret exposure

Verification

• image-native format, lint, typecheck passed
• 24 test files / 137 tests passed
• build and both headless E2E suites passed
• real authorized classic PAT: 4/4 GitHub checks ok without write probes
• desktop and mobile visual review passed
• independent review: no blocking issue
• secret scan passed