fix: preserve explicit TOP and OFFSET/FETCH limits

[debba]

Summary

• Do not add host OFFSET/FETCH pagination to SELECT statements with explicit outer TOP or OFFSET/FETCH limits.
• Keep automatic pagination for ordinary SELECTs and limits inside CTEs/subqueries.
• Ignore quoted identifiers, variables, strings and nested comments when classifying SQL.
• Add unit and live SQL Server coverage for single queries and batches.

Validation

• 214 unit tests and 3 host-model conformance tests passed.
• 2 live pagination tests passed against local SQL Server, using an isolated test database.
• cargo clippy --all-targets -- -D warnings
• cargo fmt --all -- --check

Issue scope

Refs #26. This addresses the plugin pagination half only; it intentionally does not close the issue.
The host Generate SQL modal still emits LIMIT. That will be addressed separately through an optional, backward-compatible SQL-template RPC extension in Tabularis and this plugin.