Fix codecov action failure due to missing body.html

[Copilot]

The codecov job was failing because it attempted to read ./coverage/body.html before verifying the file exists. The lcov-reporter-action doesn't guarantee this file's creation, especially when lcov-base references a non-existent comparison file.

Changes:

• Remove lcov-base parameter from lcov-reporter-action (file doesn't exist)
• Add conditional check for body.html existence before attempting to read
• Make coverage comment step conditional on file presence
• Update deprecated GitHub API calls (github.issues.* → github.rest.issues.*)

Workflow behavior:

- name: Check if body.html exists
  id: check_body
  run: |
    if [ -f ./coverage/body.html ]; then
      echo "exists=true" >> $GITHUB_OUTPUT
      cat ./coverage/body.html
    else
      echo "exists=false" >> $GITHUB_OUTPUT
      echo "body.html not found, skipping coverage comment"
    fi
- uses: actions/github-script@v6
  if: steps.check_body.outputs.exists == 'true'

The workflow now gracefully handles missing coverage reports instead of failing.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Fix codecov action failure</issue_title>
<issue_description>```log
Run cat ./coverage/body.html
cat: ./coverage/body.html: No such file or directory
Error: Process completed with exit code 1.

<agent_instructions>check github actions</agent_instructions>

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

• Fixes Fix codecov action failure #31

---

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[github-actions]

Coverage after merging copilot/fix-codecov-action-failure into master

72.73%

Coverage Report

File	Stmts	Branches	Funcs	Lines	Uncovered Lines
Sources
PublicIPAPI.swift	65.31%	100%	75%	64.44%	20–21, 24–25, 28–29, 41–50
SwiftPublicIP.swift	82.35%	100%	66.67%	85.71%	21
Tests
LinuxMain.swift	100%	100%	100%	100%
Tests/SwiftPublicIPTests
SwiftPublicIPTests.swift	72.56%	100%	69.23%	73.60%	104–108, 110–114, 116–120, 122–126, 128–132, 152–156, 17

[github-actions]

Coverage after merging copilot/fix-codecov-action-failure into master

72.73%

Coverage Report

File	Stmts	Branches	Funcs	Lines	Uncovered Lines
Sources
PublicIPAPI.swift	65.31%	100%	75%	64.44%	20–21, 24–25, 28–29, 41–50
SwiftPublicIP.swift	82.35%	100%	66.67%	85.71%	21
Tests
LinuxMain.swift	100%	100%	100%	100%
Tests/SwiftPublicIPTests
SwiftPublicIPTests.swift	72.56%	100%	69.23%	73.60%	104–108, 110–114, 116–120, 122–126, 128–132, 152–156, 17