refactor(compile): implement skip-retry iteration for quantifiers

[zharinov]

Summary

• Refactors quantifier compilation to use "skip-retry" iteration pattern
• When a pattern fails (even deep inside on a descendant), retries with next sibling
• Adds compile_skip_retry_iteration and compile_skip_retry_iteration_no_exit helpers
• Adds emit_wildcard_nav for navigating to next position with any-node match
• Includes new test definitions_nested_capture for nested definition scenarios

Test plan

• All existing tests pass (cargo test -p plotnik-lib)
• Snapshot updates reviewed and accepted