feat: resolve stdlib call: attribute placeholders via CDN registry

[shivasurya]

Summary

• Resolve call: placeholders in the attribute registry using stdlib/third-party CDN registries
• Extract dotted function calls (sqlite3.connect()) as call: placeholders in attribute extraction
• Add GetCachedModule method for cache-safe registry lookups
• Use silentLogger to prevent nil-pointer panics during lazy CDN module downloads

Changes

• resolution/attribute.go: Add resolveCallPlaceholderViaRegistry + tryRegistryLookup fallback in ResolveAttributePlaceholders
• resolution/attribute_test.go: Tests for stdlib function, constructor, thirdparty, priority, edge cases
• extraction/attributes.go: Handle attribute nodes (dotted calls) in inferFromFunctionCall
• registry/stdlib_remote.go: Add GetCachedModule method
• registry/thirdparty_remote.go: Add GetCachedModule method

Test plan

• All 29 packages pass (zero regressions)
• 100% coverage on resolveCallPlaceholderViaRegistry and tryRegistryLookup
• Stdlib function return type resolution (sqlite3.connect → sqlite3.Connection)
• Stdlib constructor resolution (configparser.ConfigParser)
• Thirdparty resolution (redis.Redis)
• Project ReturnTypes takes priority over stdlib
• E2E: pyload 153 new type-inferred resolutions, label-studio 19

🤖 Generated with Claude Code

[safedep]

SafeDep Report Summary

No dependency changes detected. Nothing to scan.

_{This report is generated by SafeDep Github App}

[github-actions]

Code Pathfinder Security Scan

No security issues detected.

Metric	Value
Files Scanned	8
Rules	88

---

_{Powered by Code Pathfinder}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.77%. Comparing base (975305a) to head (9f5e381).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #618      +/-   ##
==========================================
+ Coverage   83.66%   83.77%   +0.10%     
==========================================
  Files         155      155              
  Lines       21149    21298     +149     
==========================================
+ Hits        17695    17843     +148     
  Misses       2801     2801              
- Partials      653      654       +1     

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