feat: complete Laravel config navigation with config() helper and typed accessors

[MingJen]

Description

This PR completes the Laravel configuration navigation support by extending the existing Config:: Facade logic to include the config() helper and its fluent method chains. It also introduces a robust test suite for the underlying AST walker.

Key Changes

• Comprehensive config() Helper Support:
  • Enabled "Go to Definition" for configuration keys when using the config() helper, such as config()->get(...) or config()->string(...).
  • Fixed an issue where fully qualified helper calls (e.g., \config()->get(...)) were not correctly recognized.
• Laravel 11 Typed Accessors:
  • Updated both Config:: and config() logic to support modern typed accessors: boolean, string, integer, float, array, collection, set, prepend, and push.
• Logic Consolidation:
  • Refactored the configuration method whitelist into a shared is_config_repository_method helper to ensure consistency across different access patterns (Facade vs. Helper).
• Enhanced Test Coverage:
  • AST Walker Tests: Added extensive test cases to helpers_tests.rs for walk_all_php_expressions, covering various PHP syntax branches (Return, If, Switch, Closures, Match, etc.) to ensure reliable symbol extraction.
  • Integration Tests: Added new test scenarios in definition_laravel.rs specifically for config() instance calls and FQN helper usage.

Technical Details

• Updated src/symbol_map/extraction.rs to detect and extract symbols from method calls originating from the config() function.
• Leveraged strip_fqn_prefix to provide robust function name matching regardless of the namespace context.

Verification

• All 4,500+ existing tests passed.
• Verified new integration tests for typed accessors and namespaced helper calls.
• Confirmed cargo clippy and cargo fmt compliance.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 85.36585% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.74%. Comparing base (ac62fed) to head (16228ef).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/symbol_map/extraction.rs	85.36%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #96      +/-   ##
==========================================
+ Coverage   86.59%   86.74%   +0.15%     
==========================================
  Files         164      164              
  Lines      104416   104711     +295     
==========================================
+ Hits        90418    90833     +415     
+ Misses      13998    13878     -120     

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