LLMs frequently call ast_grep_search with regex-style patterns like
'func.*build|BuildMode|projectReferences' instead of AST patterns. The
search silently returns zero matches with no useful feedback, so the
model retries with a different regex-shaped pattern and loops.
Extract hint generation into pattern-hints.ts and add detectors for the
four dominant misuse modes:
- regex escapes (\\w, \\d, \\s, \\b)
- character-class ranges ([a-z], [0-9])
- regex wildcards (.* .+) with no meta-vars
- pure alternation (foo|bar|baz with no structural syntax)
Heuristics are designed to be safe on valid AST patterns: bitwise OR
'$A | $B' and Rust closures '|x| x + 1' are not flagged. Language-
specific shape hints (trailing-colon Python, body-less JS/TS/Go/Rust
functions) are preserved and extended to Go and Rust.
YeonGyu-Kim