1. Fix `for` keyword leaking into symbol names (~14 entries): replaced
greedy regex `<.*>` with bracket-counting parser `parse_impl_type()`
that correctly handles nested generics like `impl<T> From<Py<T>> for PyObject`.
2. Fix `where` clause leaking into symbol names (~5 entries): the new
parser stops at top-level `where` keywords.
3. Filter test functions from symbol extraction (~39 entries): skip
`#[test]`/`#[cfg(test)]` attributed functions and `test_*` named
functions in diff output.
Added 9 regression tests. All 47 tests pass.
https://claude.ai/code/session_01P1LKP6aqGt68rQAXrF6kSE
