feat: add regex search mode to the search bar

[pedrosousa13]

What

Adds a regex toggle (.*) to the tree search bar. When enabled, the typed query is compiled to a case-insensitive RegExp and a node matches when the pattern tests true against its searchKey, searchPath, or searchValue. The regex: boolean flag is plumbed through the entire search path:

• tree-worker-protocol.ts — regex added to the search request shape
• content.ts — toggle UI, sends the flag, validates the pattern, shows an inline error
• tree-worker.ts — matching loop passes the flag through and skips normalization for regex
• tree-search.ts — new compileSearchRegex helper + regex match branch alongside the existing substring scoring
• tree-worker-client.ts — sync fallback honors the flag too

Why

Substring search can't express alternation, anchors, or character classes. Regex mode gives power users precise matching across keys, paths, and values without leaving the search bar.

Behavior notes

• Regex uses the i flag, so matching is case-insensitive. The query is passed verbatim in regex mode (not trimmed/lowercased) since metacharacters and escapes are case-sensitive.
• Invalid patterns are caught at compile time, surfaced as an inline Invalid regex status, and never sent to the worker — no crash, no worker spam. Fixing the pattern clears the error.
• The toggle applies to tree search; the table view filter stays substring-only.

Known limitation

The search index lowercases values and truncates them at 200 chars (existing SEARCH_VALUE_PREVIEW_LIMIT behavior). A regex therefore only ever sees that truncated, lowercased text. Documented in a code comment on compileSearchRegex.

Test evidence

npm run typecheck — clean.

npm test — 12 files, 121 tests passing. New coverage:

• src/tree-search.test.ts — regex matches across key/path/value, case-insensitivity, alternation, invalid regex handled gracefully (no throw → empty result), and substring mode unchanged (metacharacters treated literally when off).
• src/tree-worker-client.test.ts — worker request carries the regex flag (defaults to false); sync fallback honors it.

npm run build — succeeds (dist/content.js, dist/tree-worker.js, dist/content.css).

npm run test:e2e — 20 tests passing including the new e2e/regex-search.spec.ts: toggling regex on, matching via alternation, stepping through hits, and the invalid-regex inline error path. No regressions in existing specs.

Try it

• jsonplaceholder.typicode.com/comments — open search (⌘F/Ctrl+F), enable the .* toggle, try @\w+\.biz or ^lau → highlighted matches + counter, step with Enter/Shift+Enter.
• Invalid pattern (e.g. [) → inline "Invalid regex" error, no crash.
• Note: long values are truncated at 200 chars in the search index, so regex only sees the truncated text.