refactor(web): detect hoverable symbols via Lezer highlight tags

[brendan-kellam]

Fixes SOU-1077

Summary

• Replaces the hand-maintained NODE_TYPES list in symbolHoverTargetsExtension with a tag-based check that asks each node's highlight tag whether it descends from tags.name — the same vocabulary every CodeMirror grammar already uses for syntax highlighting. New grammars now work for free; the previously-missed C++ TypeIdentifier (return types, parameter types, base classes) is now detected, along with modifier-wrapped variants like definition(variableName).
• Adds C/C++ aliasing to the language filter in codeNav/api.ts so search-based goto-definition resolves across both languages.
• Adds vitest coverage in TypeScript+JSX, Python, Go, Rust, Java, C++, and PHP with positive (expected identifiers present) and negative (keywords/punctuation absent) assertions.

Test plan

• yarn workspace @sourcebot/web vitest run src/ee/features/codeNav/components/symbolHoverPopup/symbolHoverTargetsExtension.test.ts — all 9 language tests pass
• Open a TypeScript file in the browser; hover over identifiers (variables, types, JSX components) and verify the popup appears
• Open a C++ file in the browser; hover over return types and parameter types and verify they now underline (regression vs. previous behavior where TypeIdentifier was missed)
• In a C/C++ file, verify search-based goto-definition pulls results from both C and C++ indices

🤖 Generated with Claude Code

Summary by CodeRabbit

Release Notes

• Bug Fixes

  • Enhanced symbol hover detection to identify a broader range of code identifiers across all supported languages.
  • Fixed C language code navigation to properly include C++ matches.

• Tests

  • Added comprehensive test coverage for symbol hover detection across JavaScript/TypeScript, Python, Go, Rust, Java, C++, and PHP.

[coderabbitai]

Walkthrough

The PR refactors symbol hover target detection to use Lezer highlight tags instead of hardcoded node types for broader identifier coverage, adds comprehensive multi-language test validation, enhances C/C++ language filtering, and updates the changelog.

Changes

Symbol hover targets detection

Layer / File(s)	Summary
Identifier detection via Lezer highlight tags packages/web/src/ee/features/codeNav/components/symbolHoverPopup/symbolHoverTargetsExtension.ts	Adds getStyleTags import from @lezer/highlight and replaces hardcoded NODE_TYPES with dynamic highlight tag inspection; nodes are now identified as hoverbable when their highlight tags include t.name.
Test suite for multi-language symbol detection packages/web/src/ee/features/codeNav/components/symbolHoverPopup/symbolHoverTargetsExtension.test.ts	Introduces Vitest test file with CodeMirror editor helpers and assertion utilities; validates identifier detection across JavaScript/TypeScript, Python, Go, Rust, Java, C++, and PHP; tests edge cases including zero-width nodes and missing grammar extensions.
Language filter support for C and C++ variants packages/web/src/features/codeNav/api.ts	getExpandedLanguageFilter now explicitly matches both "C" and "C++" together via an or query instead of handling them as separate language cases.
Changelog update CHANGELOG.md	Documents the switch to Lezer highlight tags for symbol hover detection in the unreleased changelog section.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• sourcebot-dev/sourcebot#325: Modifies the same symbolHoverTargetsExtension.ts file with related changes to node selection and decoration logic.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately and concisely describes the main change: refactoring symbol hover detection to use Lezer highlight tags instead of a manual node-types list.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch brendan/codenav-tag-based-symbol-detection-sou-1077

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