feat: execute MetricsQL through the shared QueryPlan

[zzylol]

Before this PR

ASAPQuery-backend exposed Prometheus/PromQL only. VictoriaMetrics clients had no independent HTTP surface, tenant-prefixed cluster routes, MetricsQL frontend identity, exact VictoriaMetrics fallback, or way to publish MetricsQL workloads into the authoritative SDS physical-plan lifecycle.

After this PR

• Adds independent VictoriaMetrics instant/range HTTP adapters, /select/{tenant}/prometheus/api/v1/query{,_range} routes, Prometheus-compatible result formatting, and exact fallback that preserves the original MetricsQL request and upstream response status/headers.
• Pins ASAPPlanner 5f37a850b367f522c7a4bda25d1727e8b44e73ee and lowers supported MetricsQL ASTs into canonical QueryExpr before shared physical selection and compilation.
• Publishes MetricsQL-tagged entries in the authoritative QueryPlan; stage/activate, ACK, hot reload, SDS descriptor validation, SummaryStore lookup, and shared DAG execution use the existing physical snapshot lifecycle.
• Keeps language identity at the boundary: MetricsQL lookup cannot match a PromQL-tagged entry with identical text, and existing PromQL lookup behavior remains intact.
• Extends shared physical bindings for selected per-series sketch materializations and process-level KLL/HLL/CMS/CountSketch readout without changing SDS descriptor meaning.
• Fails closed before publication for sum(rate(...)) and sum(increase(...)): real VictoriaMetrics differential testing showed VM extrapolation results differ from the current shared executor. These requests route to exact VictoriaMetrics fallback.
• Adds a real VictoriaMetrics E2E that imports nine samples into VictoriaMetrics, sends the same samples through backend Remote Write/precompute/SummaryStore, installs the compiled MetricsQL plan, verifies readout_lookback_ms=5000 survives JSON publication, and compares the published shared-DAG result with VictoriaMetrics.

Verification

• cargo test -p control_plane metricsql_non_equivalent_counter_rollups_fail_closed_before_publication --lib -q — passed
• VICTORIAMETRICS_URL=http://127.0.0.1:18428 cargo test -p data_plane --test victoriametrics_accelerated_e2e -- --ignored against victoriametrics/victoria-metrics:v1.126.0 — passed
  • sum(sum_over_time(m[5s])): published DAG, x-asap-execution: warm, backend 26, VictoriaMetrics 26
  • sum(increase(m[5s])): x-asap-execution: exact_fallback, backend response equals VictoriaMetrics 4
• cargo test -p data_plane --test all_sketches_process_oracle_e2e -- --nocapture — previously passed 4/4 (KLL, HLL, CMS, CountSketch); the final rerun reached the linker but this host ran out of disk and lld terminated with SIGBUS
• git diff --check — passed

Limitations

MetricsQL acceleration is a proven subset. Parser/lowering, physical publication, missing plan/binding, coverage, and runtime failures fail closed to VictoriaMetrics with a typed stage/reason. sum(rate(...)) and sum(increase(...)) are intentionally exact-fallback until the shared executor implements VictoriaMetrics extrapolation. MetricsQL modifiers and parser forms rejected by the pinned frontend also fall back. The shared PromQL types, PromQL lookup contract, and SDS descriptor semantics are unchanged.

[zzylol]

Blocking architecture/correctness issue: MetricsQlPlanCatalog is a language-specific sidecar parallel to the shared QueryPlan catalog.

control_plane/src/metricsql_plan.rs duplicates plan identity, entry lookup, and validation; ExecutableQueryPlan::execution_view clones the DAG back into a PromQL-shaped QueryPlanEntry; and ActivePhysicalPlan gains another catalog field. The sidecar's install validation checks window_ms but does not enforce the materialization's pane_origin_ms, so a MetricsQL binding can pass installation and then fail the strict phase check at read time.

Please make query identity language-tagged in the shared QueryPlan entry/catalog and publish MetricsQL entries in the existing atomic PhysicalPlanInstallRequest. Reuse QueryPlan::validate_against_catalog for the complete binding contract, including pane phase and item labels. The VictoriaMetrics protocol adapter and exact fallback can remain separate. This draft is currently conflicting with main and is not merge-ready.