feat(cost): select abstract summary window frameworks

[zzylol]

Why

Incremental maintenance determines when state changes, but does not determine the abstract window algorithm used to cover and retain the query range. Tumbling, sliding/panes, and exponential histograms have different resource and accuracy behavior and therefore belong in Planner's candidate space.

What

• Add the reusable SummaryWindowFramework enum with Tumbling, Sliding, ExponentialHistogram, and validated extension values.
• Add complete per-SummaryAgg framework assignments to streaming physical candidates.
• Rank physical alternative × lifecycle × framework combinations while preserving the provider physical_plan_id.
• Export the selected framework per summary deployment.
• Keep planner-owned window-framework IR separate from the provider-owned physical_plan_id; the latter is provenance and a downstream compilation handle, not planner IR.

Correctness rules

• Every reachable SummaryAgg has exactly one assignment; duplicates, omissions, empty extension IDs, and aliases across incompatible framework assignments fail closed.
• Generic physical alternatives and structured window candidates cannot be mixed for the same logical candidate.
• Exact tumbling/sliding choices add no window error and preserve the summary guarantee.
• Exponential-histogram accuracy is available only for the registered PromSketch EHKLL rank and EHUniv/GSum value compositions. The window bound is composed with the actual underlying summary guarantee; unknown combinations are unavailable.
• Old unbound logical CSE rewrites cannot re-enter selection after lifecycle comparison; complete physical evidence remains mandatory.

Validation

• cargo test --workspace
• cargo clippy --workspace --all-targets --all-features -- -D warnings
• cargo fmt --all -- --check

Stack: depends on #337.

Source organization

The summary-maintenance layer is split into evidence.rs, estimator.rs, window.rs, and model.rs. Window-framework assignment and EH accuracy composition are isolated from resource formulas and lifecycle ranking while reusing the existing workload, lifecycle, and window enums.