refactor: reduce cognitive complexity across codebase

[Galois123]

Summary

Refactor multiple components to reduce cognitive complexity and improve code maintainability by extracting functions, eliminating magic strings, and simplifying control flows.

Changes

This PR contains 9 focused refactor commits:

Constant Extraction

• internal/controller/run.go - Extract "unsupported language" error message to constant
• internal/core/runner/output_capture.go - Reuse error format string constant
• internal/utils/log/core.go - Deduplicate log file date format string

Function Decomposition

• internal/core/runner/nodejs/setup.go - Split releaseLibBinary into focused helper functions
• internal/core/runner/python/setup.go - Refactor both releaseLibBinary and InstallDependencies flows
• internal/core/runner/output_capture.go - Reduce complexity of output capture runner
• internal/core/runner/temp_dir.go - Extract WithTempDir helper methods
• internal/static/config.go - Split InitConfig into focused configuration loaders

Files Changed

• internal/controller/run.go (+6, -4)
• internal/core/runner/nodejs/setup.go (+59, -39)
• internal/core/runner/output_capture.go (+105, -85)
• internal/core/runner/python/setup.go (+116, -77)
• internal/core/runner/temp_dir.go (+40, -33)
• internal/static/config.go (+103, -80)
• internal/utils/log/core.go (+5, -3)

Benefits

• Improved Readability: Smaller, focused functions are easier to understand
• Better Maintainability: Each function has a single responsibility
• Easier Testing: Smaller functions can be tested independently
• Reduced Cognitive Load: Less nesting and clearer control flow

Testing

All existing tests pass. No functional changes - purely structural improvements.