## Description

The JSON repair utility in `litellm/litellm_core_utils/prompt_templates/common_utils.py` has two bugs that cause `JSONDecodeError` when processing tool call arguments:

### Bug 1: Premature bracket closure when truncated inside a string

When a tool call argument is truncated inside a string value (e.g. a long shell heredoc cut off before the closing `"`), `_repair_json()` closes all open brackets and returns prematurely. This produces invalid JSON because the unterminated string value is never properly closed.

**Example:** A tool call with a long `Write` command like: ``` Write(code="very long file content that gets truncated... ``` The repair utility closes the outer `{}` without closing the string, resulting in a `JSONDecodeError`.

### Bug 2: Raw newlines inside JSON string values are not escaped

LLM tool call arguments containing shell heredocs or multi-line strings often include literal `\n` and `\r` characters inside JSON string values, which is not valid JSON. The repair utility does not escape these before attempting to parse, causing parse failures.

**Example:** A Bash tool call emitting: ``` Write(code="line1\nline2\nline3") ``` The raw newlines inside…