Search file contents for a regex or literal pattern. Output is grouped by file and uses `LINE#HASH│content` format — the same anchors the read tool produces. This means grep results can be passed directly to edit or insert without an intermediate read.

Respects .gitignore by default.

**Parameters:**
- `pattern` (required) — regex or literal search pattern
- `path` (optional) — directory or file to search; defaults to the project root
- `glob` (optional) — file filter, e.g. `*.ts` or `**/*.spec.ts`
- `ignoreCase` (optional) — case-insensitive mode; default false
- `literal` (optional) — treat pattern as a literal string; default false
- `context` (optional) — lines of context before/after each match; default 0
- `limit` (optional) — maximum matches returned; default 100

Output is truncated at 100 matches or 50KB, whichever comes first. Capped matches display a truncation notice. Long lines (>500 chars) are truncated with a `…` suffix.