v3 SQL: dim-link-aware filter pushdown into inner subquery scopes

[shangyian]

Summary

This PR overhauls how _resolve_pushdown_filters_for_cte decides where to inject user-supplied dimension filters within a CTE body, closing several regressions in the original "walk every source-table reference" pass (#2166) and bringing v3's pushdown placement closer to v2's behavior.

For context, the filter pushdown in v3 had two known regressions as compared to v2:

1. Spark OOMs when the same source table was referenced inside a nested subquery but only the top-level reference got the partition predicate.
2. Column doesn't exist errors when an outer subquery alias collided with a deeper Table alias, causing the filter to be retargeted into the wrong scope.

Earlier attempts to fix these (the "walk every source-table reference" change) also went too far: they pushed filters into tables that incidentally shared a column name with the filter's dim but weren't actually linked to it, diverging from v2.

_resolve_pushdown_filters_for_cte now does two complementary passes:

1. Alias-substitution pass: For each alias used in the primary rewrite at target_select, find every sibling ast.Table ref to the same physical source elsewhere in the CTE body and inject a retargeted copy. Restores the v2 partition-prune-everywhere behavior for self-references.
2. Column-aware retargeting pass: For each ast.Select scope inside the CTE body (including secondary set-op arms), builds a resolver map from:

• Dim-link entries: for each node referenced in the scope's FROM, register one entry per foreign_keys_reversed row from its dimension links. This is the only route by which filters get pushed at inner scopes.
• Dim-self entries: when the scope's table is itself a dimension node, register its PK columns as self-pointing entries.

Test Plan

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Deployment Plan

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