Replace httr with httr2 in spk_geoserv_dlv()

[NewGraphEnvironment]

Closes #9

Migrates from deprecated httr to actively maintained httr2:

• httr::GET() → httr2::request() |> req_url_query() |> req_perform()
• httr::write_disk() → req_perform(path = ...)
• httr::status_code() → httr2::resp_status()
• cat() messages → cli::cli_alert_success/cli_abort for consistency

All 44 tests passing.

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

[claude]

Review

Summary: Clean migration from deprecated httr to httr2. Code changes are correct and follow best practices.

Correctness: ✅

• Proper httr2 API usage: request() |> req_url_query() |> req_perform()
• Correct parameter unpacking with !!! in req_url_query()
• req_error(is_error = \(resp) FALSE) correctly prevents automatic errors (allowing manual status check)
• req_perform(path = file_out) replaces write_disk() correctly
• Status code extraction with resp_status() is correct

Error Handling: ✅

• File is written before status check (line 95), then status checked (line 97)
• If status != 200, function aborts with cli_abort (line 113)
• Error function correctly prevents automatic throwing so manual check can happen

Consistency: ✅

• Messaging upgraded to cli functions (cli_alert_success, cli_abort)
• All httr imports removed from NAMESPACE, httr2 imports added
• DESCRIPTION dependency updated

Potential Issue: ⚠️ Minor - Non-blocking
Line 94: req_error(is_error = \(resp) FALSE) disables automatic error handling, but if the file write fails (e.g., disk full, permissions), the function will still write a file and only detect the error at status check. This is acceptable for WFS responses (which return 200 + error XML), but worth noting.

Recommendation: Approve and merge. All 44 tests reportedly passing per PR description.