feat(build): download icons during package build

[mairas]

Summary

Add icon download step to build-source.sh that downloads missing icons from CDN URLs stored in each app's metadata.yaml before building packages.

How it works

1. Before building app packages, the script iterates through all apps
2. For apps without an existing icon file, it extracts the icon: URL from metadata.yaml
3. Downloads the icon from the upstream CasaOS CDN
4. The icon is then included in the generated .deb package

Why this approach

• No repo bloat: Icons are downloaded at build time, not stored in the repo
• Always fresh: Icons come from the authoritative upstream source
• Reliable: All 144 apps have icon URLs in their metadata (set during conversion)
• Graceful fallback: Apps that fail to download icons still build successfully

Test plan

• CI builds successfully
• Icon download step runs and reports results
• Generated packages include icons
• Icons display correctly in Homarr dashboard

Closes #39

🤖 Generated with Claude Code

[github-actions]

❌ Build failed for casaos

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[mairas]

Code Review

Summary

This PR adds automatic icon downloading from CasaOS CDN URLs during package build. The approach is sound - downloading at build time avoids repo bloat while ensuring icons are available.

Issues Found

1. Build failure (fixed in dc366c0): The original code used ((counter++)) which returns exit code 1 when counter is 0, causing set -e to terminate. The fix correctly changed this to : $((counter++)).

2. Potential grep failure: Line 130 could still fail with set -e if grep finds no matches:

   icon_url=$(grep -E '^icon:\s*https?://' "$metadata_file" 2>/dev/null | sed 's/^icon:\s*//' | tr -d ' ')

   If any metadata file lacks a matching icon URL pattern, grep returns exit code 1. Consider adding || true:

   icon_url=$(grep -E '^icon:\s*https?://' "$metadata_file" 2>/dev/null | sed 's/^icon:\s*//' | tr -d ' ' || true)

3. Metadata format warnings (separate issue): The warnings about deprecated package_name field are from the CasaOS converter generating outdated metadata, not this PR. Will track separately.

What's Good

• Clean approach: icons downloaded at build time, not stored in repo
• Graceful fallback: apps without icons still build
• Good reporting of download statistics

Recommendation

If the current build passes, the PR is ready to merge. If it fails due to the grep issue mentioned above, the fix is straightforward.

[github-actions]

✅ Build successful for casaos

📦 Built 145 packages

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