fix: resolve sonarqube issues

[ClaudiaFang]

Summary

Resolve issues reported by SonarQube for the Obsidian Git Files Sync plugin.

Scope

• Review current SonarQube findings.
• Fix code smells, bugs, security hotspots, and maintainability issues where applicable.
• Add or update tests for behavioral changes.
• Run lint, tests, and build before closing.

Acceptance Criteria

• SonarQube report no longer shows the targeted issues.
• Existing functionality remains unchanged.

git-file-sync@1.2.0 lint
eslint .,
git-file-sync@1.2.0 build
tsc -noEmit -skipLibCheck && node esbuild.config.mjs production, and relevant Vitest tests pass.

[ClaudiaFang]

Backlog priority review — 2026-08-04

Priority: P2

Reason: Code-quality findings can improve maintainability, but this umbrella ticket does not identify the current findings, severity, false positives, or user-facing impact. Treating all Sonar findings as one urgent fix can produce churn without product value.

Scheduling note: Refresh the report, triage security/bug findings separately, and convert only accepted items into bounded tasks. Escalate confirmed vulnerabilities or correctness bugs independently.