fix(editor): JSONC comments read as comments, not errors (#312)

[Maxaubert]

Closes #312.

Owner, 2026-10-07: "comments in jsonc arent read as comments in prism" (a wrangler.jsonc with a red squiggle under every // line, drawn in the plain text colour).

Cause

codeLang.ts mapped .jsonc and .json5 to the strict @codemirror/lang-json grammar, and CodeView attached jsonLinter (JSON.parse) to them. The Lezer JSON grammar has no comment token, so a comment became error nodes: no comment tag (so no comment colour, although codeTheme.ts maps t.comment / t.lineComment / t.blockComment to --p-code-comment) and a squiggle from both linters. tsconfig.json and other JSON-with-comments names went the same way through .json.

Fix

• lib/jsoncMode.ts (new): a small StreamParser that emits the JSON grammar's own tags (propertyName, string, number, bool, null, brace, squareBracket, separator) plus lineComment / blockComment, with smart indent, comment tokens for Ctrl+/, and a brace fold service. A unit test holds that a comment-free document colours exactly as the JSON grammar colours it.
• codeLint.ts: blankJsonc turns comments and trailing commas into spaces with every offset and line break kept, then jsoncErrors runs JSON.parse on the result, so a missing comma or an unclosed brace is still underlined at its real place; an unclosed /* is reported. lintFor(lang) decides the checker (JSON: grammar + JSON.parse; JSONC: jsoncErrors only; JSON5: none; stream lexers: none).
• codeLang.ts: lint field on a language; JSONC for .jsonc, tsconfig.json, tsconfig.*.json, jsconfig.json, jsconfig.*.json, .eslintrc, .eslintrc.json, .babelrc, .babelrc.json, devcontainer.json, .devcontainer.json, wrangler.json, turbo.json, biome.json, deno.json, and every .json inside a .vscode folder (langFor(name, path)). .json5 colours the same with no linter (bare keys and single quotes would be false errors). Plain .json and .ipynb stay strict.
• CodeView.tsx: langFor(name, path) and lintFor(lang) replace the inline regex.
• No new dependency.

Files

• src/renderer/src/lib/jsoncMode.ts (new)
• src/renderer/src/lib/jsonc.test.ts (new, 13 tests)
• src/renderer/src/lib/codeLang.ts
• src/renderer/src/lib/codeLint.ts
• src/renderer/src/components/CodeView.tsx
• tools/e2e/run.mjs (jsonc scenario)
• CLAUDE.md (rule with the owner's words)
• package.json, package-lock.json (0.92.1 to 0.92.2)

Gates

• npm run typecheck: clean
• npm run lint: 0 errors (7 existing warnings, none in changed files)
• npx vitest run: 171 files passed, 2539 tests passed (2 skipped)
• New jsonc e2e: opens a wrangler.jsonc like the owner's, asserts no squiggles, every comment span wears the theme's comment colour (italic), tsconfig.json with comments and trailing commas is clean, and a missing comma in a .jsonc is underlined once. FAILS on main (6 failures, verified by running it against main's src), passes here. Screenshots .e2e/shots/jsonc.png, jsonc-error.png looked at.
• Editor e2e one at a time: jsonc, code, treeNav, edit, reload, tail, md, previewClears all pass.
• npm run e2e:terminal: all pass (a first run had one tabs failure, which passed alone and on a full rerun of the gate; the change does not touch tabs).

🤖 Generated with Claude Code

https://claude.ai/code/session_01FHHaWKR4M5QtW7Wecyuk4t