Feature Request: Add HCL/Terraform language support

[sachajw]

What would be involved

Looking at the existing language extractors in src/extraction/languages/, it seems like adding HCL would need:

1. Tree-sitter grammars — tree-sitter-hcl and tree-sitter-terraform are available as WASM builds from the tree-sitter-hcl
   (https://github.com/Mitchell-Sandrock/tree-sitter-hcl) project
2. Grammar registration in src/extraction/grammars.ts — map .hcl → hcl and .tf/.tfvars → terraform with WASM paths
3. Language extractor (src/extraction/languages/hcl.ts) — HCL's primary construct is the block node, where named blocks follow the pattern:
   - resource "aws_instance" "web" { ... } — block type + labels
   - variable "name" { ... }
   - module "name" { ... }
   - data "type" "name" { ... }

The block name can be derived from concatenating the identifier and string_lit children of the block (e.g., resource.aws_instance.web).

Use cases

• Navigate Terraform modules and their dependencies
• Find all references to a specific resource across a large monorepo
• Trace variable/output chains between modules
• Search for resource types (aws_instance, azurerm_kubernetes_cluster, etc.)

Environment

• CodeGraph v0.9.2
• macOS (arm64)