feat: adopt versioned Planner kernels and typed physical selection

[zzylol]

Stacked on #806.

Why

The backend must use Planner-owned computation and preserve sampling metadata through stored-state reads. The integrated Planner now also types series identity before physical selection and compiles the remaining requested PromQL shapes.

What

Remove the UnivMon shim and private codec mirrors; use validated Planner kernel accessors and in-place delta updates. Version sampled and exact payloads, including durable frame tags, and reject retired formats. Type candidates before selection, remove reselection, retain safe whole-query fallback for unbindable candidates, and price native timing using its installed windows.

Pin Planner integration a049a3b6c17cee4c51c79e478799b32280a7d71d. Lock changes preserve every dependency version and sketchlib revision; the new Planner label_replace dependency requires one reference to the already locked regex package.

Before this PR

Sampled edge frames were rejected; stored payloads omitted sampling metadata; duplicate backend code implemented UnivMon and decoded private kernel layouts. Candidate selection needed a typed retry.

After this PR

Sampled frames retain their probability through updates, window readout, persistence, and recovery. Old formats fail explicitly. Logical candidates carry series identity up front and execution stays with Planner kernels and physical programs.

Review dependency

Open PR #791 overlaps the SDS ownership and stored-state decoding changes already carried by #793/#805. It uses an older Planner pin and should be reconciled before either overlapping route is merged. This PR does not merge either route.

Validation

Independent review completed for codec, delta atomicity, upfront typing, native pricing, and stored-frame routing. All required checks passed at the final Planner pin:

• Formatting and all-target workspace Clippy with warnings denied.
• Workspace library tests, including 43 stored-state tests and 882 data-plane tests.
• Complete control-plane test suite, including native placement pricing.
• All 29 compatibility process tests, including persistence/restart, two-source immutable and revisable maintenance, mixed placement, and successive warm evaluations within the startup limit.

Regressions were established before the fixes. Planner's corresponding full workspace validation also passed.

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