feat(ingestion): add Solidity language support

[JaCoderX]

Summary

Adds first-class Solidity (.sol) support via a vendored tree-sitter-solidity@1.1.0 grammar (ABI 13 / optional, same pattern as Dart/Kotlin/Swift), with LanguageProvider wiring, extractors, scope resolution for Foundry-style projects, fixtures/tests, web WASM registration, and docs/CHANGELOG.

Motivation / context

Closes #531. Smart-contract repos were previously unindexed (no DEFINES/CALLS from .sol), so MCP query / context / impact could not answer from contracts. This lands Phase 1–3-quality Solidity ingestion so Foundry/Hardhat-style trees produce a usable graph.

Areas touched

• gitnexus/ (CLI / core / MCP server)
• gitnexus-web/ (Vite / React UI)
• .github/ (workflows, actions)
• eval/ or other tooling
• Docs / agent config only (AGENTS.md, CLAUDE.md, .cursor/, llms.txt, etc.)

Also: gitnexus-shared/ (language enum / detection / classification), root README.md + CHANGELOG.md, gitnexus/CHANGELOG.md.

Scope & constraints

In scope

• Vendored tree-sitter-solidity@1.1.0 under gitnexus/vendor/ (pinned for tree-sitter@0.21.1 ABI; optional via GITNEXUS_SKIP_OPTIONAL_GRAMMARS=1)
• CLI LanguageProvider + extractors: contracts / interfaces / libraries, functions, constructors, modifiers (definitions + invocations), events, inheritance
• Import resolution: relative paths, named imports, Foundry remappings (remappings.txt / foundry.toml)
• using for, emit/revert edges, this / super receiver binding, Foundry noise filter (vm / msg / abi)
• Unit + integration fixtures under test/fixtures/lang-resolution/solidity-*
• Web: WASM grammar map + Vite copy of tree-sitter-solidity.wasm (indexing remains server-side via gitnexus serve)
• Linux Docker FTS smoke script: gitnexus/scripts/docker-fts-validate.sh (GITNEXUS_FTS_QUERY, default contract)
• README supported-languages matrix + Unreleased CHANGELOG entries

Explicitly out of scope / not done here

• Solidity CFG / PDG / --pdg taint
• Yul, delegatecall, and full dynamic-dispatch fidelity
• Full in-browser client-side re-index (WASM binary published for future use only)
• Hardhat-specific config parsers beyond remapping-compatible paths
• Perfect resolution of every edge on large protocol corpora (validated on a large Foundry monorepo; evidence anonymized below)

Implementation notes

• Grammar vendoring mirrors Dart/Kotlin/Swift: build from vendor/, do not bump to tree-sitter-solidity 1.2.x (ABI 15) without a runtime upgrade.
• Modifier invocations create CALLS edges; inherited modifiers use MRO-aware pickImplicitThisOverload when free-call fallback is ambiguous.
• Windows host Ladybug FTS may fail to load (DLL); hybrid BM25 validation should use Linux Docker. Graph tools are unaffected on Windows.
• Indexing Solidity in the web UI goes through gitnexus serve (native grammars), not browser WASM parse.

Testing & verification

• cd gitnexus && npm test (Solidity unit + integration fixtures during development)
• cd gitnexus && npm run test:integration (if distinct from npm test in this repo — run before merge if CI doesn’t)
• cd gitnexus && npx tsc --noEmit (during development)
• cd gitnexus-web && npm test (WASM / upload-filter / solidity-syntax tests added)
• cd gitnexus-web && npx tsc -b --noEmit
• Manual / Playwright E2E (not required for this PR)

Additional verification

• Analyzed a large Foundry Solidity monorepo (OpenZeppelin mirrored under lib/ for imports): ~13.6k nodes / ~35k edges; modifier → OZ nonReentrant, library CALLS, remapping IMPORTS, METHOD_OVERRIDES present; hybrid FTS OK under Linux Docker.
• FTS smoke (Linux): mount repo + corpus, run gitnexus/scripts/docker-fts-validate.sh (override GITNEXUS_FTS_QUERY as needed).

Risk & rollout

• Non-breaking for existing languages; Solidity is an additive optional grammar.
• Install hosts without a C++ toolchain can set GITNEXUS_SKIP_OPTIONAL_GRAMMARS=1 (Solidity skipped with other optional grammars).
• After upgrade: re-run npx gitnexus analyze (or --force) on Solidity repos to populate the new graph.
• Release notes: cover under Unreleased → Added (CHANGELOG already drafted).

Checklist

• PR body meets repo minimum length (workflow may label short descriptions)
• If AGENTS.md / overlays changed: headers, scope block, and changelog updated per project conventions (N/A — not changed)
• No secrets, tokens, or machine-specific paths committed

[vercel]

@JaCoderX is attempting to deploy a commit to the NexusCore Team on Vercel.

A member of the Team first needs to authorize it.

[koriyoshi2041]

Did a focused local pass on this because the hosted checks have not run beyond labeler/Vercel yet.

Environment: macOS arm64, Node v25.6.1, npm 11.9.0.

Results:

• npm install in gitnexus/: Solidity native binding built from source successfully. The first install hit the existing monorepo setup caveat where scripts/build.js expects ../gitnexus-shared/node_modules/.bin/tsc; after npm install in gitnexus-shared/, build proceeded.
• npx vitest run test/integration/resolvers/solidity.test.ts: 24/24 passed.
• npx vitest run test/unit/solidity-structure.test.ts test/unit/solidity-import-resolver.test.ts test/unit/solidity-named-imports.test.ts test/unit/solidity-heritage-captures.test.ts test/unit/scope-resolution/solidity-receiver-binding.test.ts test/unit/parser-loader.test.ts test/unit/parser-loader-skip-optional.test.ts: 49/49 passed.
• npx tsc --noEmit: passed.

One small coverage suggestion: the PR body and implementation mention foundry.toml remappings, but the new integration fixture appears to cover remappings.txt only (solidity-remappings/remappings.txt). A tiny foundry.toml fixture would lock that advertised path too, especially since the parser is intentionally regex/minimal rather than a TOML dependency.

[JaCoderX]

Thanks @koriyoshi2041 for reviewing and the feedback.

Agreed on the gap: foundry.toml remappings were implemented (regex/minimal parser; foundry.toml then remappings.txt override) but only remappings.txt was fixture-covered.

Pushed a follow-up that locks the advertised path:

• unit tests for multiline + single-line foundry.toml, and remappings.txt override
• integration fixture solidity-foundry-toml-remappings/ with foundry.toml only (no remappings.txt)

The gitnexus-shared → gitnexus install order you hit is the existing monorepo setup caveat; unrelated to this change.