Summary

Adds first-class Julia (.jl) indexing to CodeGraph using the tree-sitter-julia grammar.

This PR extends and supersedes the groundwork in #244 by @kongdd (happy to co-author), with additional handling for common Julia AST shapes seen in real-world packages (including Julia 1.11):

• Structs without block wrappers — struct_definition may use typed_expression children instead of a body / block; extractStruct resolves the body via resolveBody for consistency with interface extraction.
• Functions without block wrappers — many files use a flat statement list directly under function_definition. Handled in juliaExtractor.visitNode: the first signature-shaped child (signature / call_expression / typed_expression / where_expression) is treated as the declaration head, and the remaining children are walked via ctx.visitFunctionBody so nested calls (e.g. out_neighbors, topological_sort) are still indexed. resolveBody deliberately returns null for these so the core visitFunctionBody cannot re-enter extractFunction and recurse.
• One-line definitions — e.g. f(x) = expr via assignment handling (not covered in add support for Julia #244).
• module nodes — module_definition mapped to module kind so members are namespace-scoped in qualified_name.
• macrocall_expression — added to callTypes.
• Vendored WASM — tree-sitter-julia.wasm committed under src/extraction/wasm/ (the grammar is not published in tree-sitter-wasms@0.1.11; npm-only loading would fail in CI and offline installs). Same vendoring pattern as lua / luau / pascal / scala.

Also adds the optional getName hook on LanguageExtractor (as proposed in #244) and wires it through extractName.

Test plan

• npm run build
• npm test -- --run -t "Julia Extraction" — 11 / 11 tests pass, covering: language detection, top-level functions, signatures, macros, structs without block, abstract types, modules, imports / using, one-line f(x) = expr, and call extraction inside flat bodies.
• Full npm test — extraction & installer-targets suites pass.
• Real-world: codegraph index over a Julia workspace (~120 .jl files) — julia shows up under "Files by Language", with function / struct / module / import nodes and calls / imports edges in the index.

Notes for maintainers

• tree-sitter-julia is a devDependency only for rebuilding WASM; runtime uses the committed src/extraction/wasm/tree-sitter-julia.wasm binary.
• Rebased onto current main; no merge conflicts.
• New getName hook on LanguageExtractor is optional and used only by Julia today; existing extractors are unaffected.