fix: parse tree-sitter sequence syntax as Seq instead of wildcard Tree

[zharinov]

Summary

• Tree-sitter style ((a) (b)) now parses as Seq node instead of wildcard Tree with children
• Fixes ((x)) being interpreted as "any node containing x as child" instead of "sequence containing x"
• Adds regression tests for tree-sitter sequence parsing

Why

Pattern ((expression_statement) @s)* @outer was returning empty results because ((x)) was parsed as a wildcard node match + descend, rather than a single-item sequence. This broke tree-sitter compatibility for users migrating queries.