feat: add terraform import block support for existing resources

[endavis]

Description

Add support for Terraform import blocks via a new import_id field on resource configurations. When a resource has import_id set, InfraFoundry automatically generates the corresponding Terraform import {} block in the output, allowing users to adopt existing infrastructure into Terraform state without running manual terraform import commands.

The implementation is framework-level in TerraformGeneratorMixin.render_and_write_terraform, so it works across all providers with no per-provider changes.

Related Issue

Addresses #387

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code refactoring
• Performance improvement
• Test improvement

Changes Made

• Added import_id: str | None field to ResourceConfig model
• Added _generate_import_blocks method to TerraformGeneratorMixin that scans rendered Terraform for resource declarations and matches them against resources with import_id
• Updated render_and_write_terraform to prepend import blocks when present
• Passed import_id through all three config loaders (provider-centric, resource-centric, package)
• Added 17 unit tests covering import block generation, multiple resources, no-op when absent, regex matching, and integration with render_and_write_terraform
• Updated configuration docs (overview, YAML-only config, state management) to document import_id

Testing

• All existing tests pass
• Added new tests for new functionality (17 tests in tests/unit/test_import_blocks.py)
• doit check passes (format, lint, type-check, security, spell-check, tests)

Checklist

• My code follows the code style of this project (ran doit format)
• I have run linting checks (doit lint)
• I have run type checking (doit type_check)
• I have added tests that prove my fix is effective or that my feature works
• All new and existing tests pass (doit test)
• I have updated the documentation accordingly
• I have updated the CHANGELOG.md
• My changes generate no new warnings

[github-actions]

Benchmark

Details

Benchmark suite	Current: 272f291	Previous: 2a4d52e	Ratio
tests/benchmarks/test_placeholder.py::test_import_time	12617.801265118283 iter/sec (stddev: 0.000004846046533051096)	9630.1489066661 iter/sec (stddev: 0.0000054635757391543555)	0.76

This comment was automatically generated by workflow using github-action-benchmark.