Fix query rewrite rules to match by source table

[acmeguy]

Summary

• Query rewrite rules are defined against database table names (e.g. semantic_events) but were matching against Cube.js cube names, which can differ
• Now parses active dataschemas to build a cube→source table mapping, cached by schema version
• Rules apply to all cubes backed by the target table, regardless of cube name
• Skips rule application when a cube lacks the rule's dimension (e.g. array join cubes without partition)

Test plan

• Create a cube with a name different from its source table (e.g. cube MyEvents backed by semantic_events)
• Verify partition filter is applied when querying MyEvents
• Verify cubes not backed by internal tables are unaffected by partition rules
• Verify cubes that lack the partition dimension are skipped gracefully

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