Fix filters after outer joins silently turning them into inner joins

[shangyian]

Summary

When a v3 measures query joins to a dim via RIGHT OUTER / FULL OUTER, filters on adjacent left-joined dims land in the outer where after the outer join. This silently breaks the outer join's preservation semantics and preserved-side rows (the ones the outer join exists to keep) get dropped whenever the filter's column is NULL on them. This PR fixes that and consolidates the related filter-routing logic.

For queries that mix left join-with-filter and right/full outer, the result rows differ from before this PR: preserved-side rows from the outer join now survive when no matching fact row exists, matching the user's intent of right outer (preserve everything from the right). Queries that don't involve right/full are unaffected (pure-LEFT-chain filter narrowing semantics remain as today).

OUTER-JOIN-safe filter routing in CTE bodies

When a right or full outer join is present in the chain, every left/inner-joined dim that has a defeating filter is consolidated into a <parent>_filtered CTE that applies its filters before the outer join reaches it. The outer FROM then reads from the filtered CTE, and the outer join preserves correctly.

Absorbed-dim references (t2.client_name) are rewritten to the wrapper alias (t1.client_name) across projection, GROUP BY, kept-join ONs, and remaining WHERE atoms. The absorber handles both qualification styles DJ uses: _table-set (projection/GROUP BY) and name.namespace-set (filter atoms via _add_table_prefixes_to_filter).

Add COALESCE for outer join FKs

When the full-skip optimization substitutes a dim's PK with the fact's FK and a sibling dim shares the same FK alignment via its own link, the projection now emits COALESCE(t1.foreign_key, t3.primary_key) AS final_key and the GROUP BY mirrors the COALESCE. This preserves correct values under outer joins that null-fill the fact side.

Redundant outer-WHERE cleanup

The parent-alias atoms that are already pushed into the parent CTE (via the existing pushdown machinery) are no longer duplicated into the outer SELECT's WHERE. They were redundant and, under downstream OUTER JOINs, actively unsafe.

Test Plan

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• make test shows 100% unit test coverage

Deployment Plan

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