[repo-assist] Dispose sitemap file stream after deserialization

[github-actions]

Warning

Threat Detection Engine Failure — The analysis engine could not complete. This is a tooling failure, not a security finding.

What happened

The threat detection engine failed to produce results.

Review the workflow run logs for details.

🤖 This PR was created by Repo Assist, an automated AI assistant.

Closes no issue; this is a focused maintenance improvement.

Summary

Dispose the FileStream opened while loading Chapters/sitemap.json in SiteMappingService.

Root cause

The constructor passed File.OpenRead(path) directly to JsonSerializer.Deserialize, leaving the stream undisposed after deserialization and retaining a file handle for the lifetime of the process.

Fix rationale

The stream is now held in a using declaration, so it is disposed immediately after deserialization while preserving the existing SiteMappings behavior. The unused import in the same file was removed.

Test Status

• dotnet restore --ignore-failed-sources — passed.
• dotnet build --configuration Release --no-restore — passed.
• dotnet test --configuration Release --no-build — 174 passed; 2 unrelated external-service integration tests failed (CaptchaService_Verify_Success and KnownBreachedPassword_IsDetected) because their remote services were unavailable.
• git diff --check — passed.

No breaking changes or new dependencies.

Warning

Firewall blocked 2 domains

The following domains were blocked by the firewall during workflow execution:

• api.hcaptcha.com
• api.pwnedpasswords.com

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "api.hcaptcha.com"
    - "api.pwnedpasswords.com"

See Network Configuration for more information.

Generated by 🌈 Repo Assist, see workflow run. Learn more.
_{Comment /repo-assist to run again}

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

gh aw add githubnext/agentics/workflows/repo-assist.md@4bc8419fad05e6b032741cbfd189986700bcf71c

[github-actions]

Threat detection produced a warning for this pull request output.

These changes need to be scrutinized before merge and only merged after a careful manual review.

• Detection reason: agent_failure
• Review workflow run logs: https://github.com/IntelliTect/EssentialCSharp.Web/actions/runs/36970487845