cpf/enhancement: Implement relative import resolution

[shivasurya]

This PR implements comprehensive relative import resolution for Python using a 3-pass algorithm. It extends the import extraction system to handle Python's relative import syntax with dot notation.

Key Changes:

1. Added FileToModule reverse mapping to ModuleRegistry

   • Enables O(1) lookup from file path to module path
   • Required for resolving relative imports
   • Updated AddModule() to maintain bidirectional mapping

2. Implemented resolveRelativeImport() function

   • Handles single dot (.) for current package
   • Handles multiple dots (.., ...) for parent/grandparent packages
   • Navigates package hierarchy using module path components
   • Clamps excessive dots to root package level
   • Falls back gracefully when file not in registry

3. Enhanced processImportFromStatement() for relative imports

   • Detects relative_import nodes in tree-sitter AST
   • Extracts import_prefix (dots) and optional module suffix
   • Resolves relative paths to absolute module paths before adding to ImportMap

4. Comprehensive test coverage (94.5% overall)

   • Unit tests for resolveRelativeImport with various dot counts
   • Integration tests with ExtractImports
   • Tests for deeply nested packages
   • Tests for mixed absolute and relative imports
   • Real fixture files with project structure

Relative Import Examples:

• from . import utils → "currentpackage.utils"
• from .. import config → "parentpackage.config"
• from ..utils import helper → "parentpackage.utils.helper"
• from ...db import query → "grandparent.db.query"

Test Fixtures:

• Created myapp/submodule/handler.py with all relative import styles
• Created supporting package structure with init.py files
• Tests verify correct resolution across package hierarchy

Checklist:

• Tests passing (gradle testGo)?
• Lint passing (golangci-lint run this requires golangci-lint)?

[safedep]

SafeDep Report Summary

No dependency changes detected. Nothing to scan.

_{This report is generated by SafeDep Github App}

[codecov]

Codecov Report

❌ Patch coverage is 96.29630% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.34%. Comparing base (5454e99) to head (722556b).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
sourcecode-parser/graph/callgraph/imports.go	96.15%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #325      +/-   ##
==========================================
+ Coverage   73.94%   74.34%   +0.40%     
==========================================
  Files          26       26              
  Lines        2675     2717      +42     
==========================================
+ Hits         1978     2020      +42     
  Misses        647      647              
  Partials       50       50              

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