fix(edge): P0/P1/P2 code-review fixes across gorilla-go, precompute-go, asapedgeprocessor (+Rust parity, docs)

[zzylol]

Implements the P0/P1/P2 fixes from a code review of the edge stack (asap-gorilla-go, asap-precompute-go, asapedgeprocessor), plus Rust byte-parity reconciliation, the B6 fix in both runtimes, and a delta-baseline design doc. ASAPQuery-backend needs no code changes (verified against its current main).

P0 — correctness / silent data loss

• HLL & CountSketch full-state ApplyDelta (asap-precompute-go/sketches/{hll,countsketch}.go): tried delta-decode first, so a full-state envelope silently merged to 0. Now full-state-first (mirrors CMS). Real-wrapper regression test added.
• Unsupported metric types no longer dropped (asapedgeprocessor/ingest.go): Histogram/Summary/ExponentialHistogram were silently dropped from passthrough and never archived. Now always forwarded raw + counted.
• Unbounded maps capped (warm_sketch.go/warm_sum.go): wired MaxSeries/OnOverflow (+ sum-group cap), default 100000.
• Shutdown durable drain (processor.go): no longer skips cold-part/spool drain when the flush-wait ctx expires.
• CMS dim validation (sketches/cms.go): non-pow2 cols panicked on query; now cols→next pow2 + rows clamped to the 64-bit row-hash budget. Mirrored into Rust for asap_sketchlib ↔ sketchlib-go byte-format harmonization (cross-language parity) #243 parity.
• OOODrop per-fragment delta (asap-gorilla-go/fragment.go): cumulative counter was summed per fragment (~N·D over-count); now a per-flush delta.

P1 — designed but missing

• Control-plane wiring (asapedgeprocessor/control_plane.go): optional control_channel block; Start() polls and applies config via Precompute.UpdateConfig in-place. Disabled by default.
• Delta transmission wired per-family — default OFF (see backend-compat + design note below).
• AllowedLateness set to match cold ReorderGrace.
• Regex label matchers (precompute-go/matchers.go): =~/!~, Prometheus-anchored.
• Sliding windows (precompute-go/window.go) implemented, with a guardrail doc that they must not feed the additive-merge backend.

P2 — hygiene

gorilla-go: INT decode cursor advance, README rewrite (removed non-existent GORILLA1 API), ASAPCC1/intchunk archive-tier doc, dead code, low-sev guards. precompute-go: quantile clamp, telemetry counters. edge: sum start>end + maxObserved reset, observe-error counter, cold seal/ship dedup, -race concurrent ConsumeMetrics test.

B6 — CountSketch/CMS observation subject (fixed in BOTH runtimes)

• Go edge (warm_sketch.go): CountSketch now counts the attribute-set (key=AttributesKey, weight 1), and CMS counts the attribute-set via KindBytes — not the degenerate metric-name key.
• Rust OTAP edge (asap-precompute-rs): SketchObserver::observe(sketch, v) → observe(sketch, obs) so the family-specific observer keys itself from obs.labels. This fixes CountSketch (was counting the metric name) and the CMS-records-nothing bug (CMS errored on the OTAP Float-kind path). No Go change, no plugin/lifecycle plumbing; cargo test + --features otap green; stale lifecycle test fixed + attribute-set tests added.

Design decision — sketches carry no metric scalars

Per project direction: no sketch (DDSketch included) carries metric count/sum/min/max in the full proto or the delta proto. Exact aggregates are separate, controller-provisioned exact edge aggregations (e.g. the existing sum family → delta-Sum metric; a MinMax family), never fields on the sketch. This makes delta transmission uniformly sketch-state-only across all families. docs/delta-baseline-contract.md is updated to this model. The actual proto field removal is a queued follow-up effort (see below).

Backend compatibility (ASAPQuery-backend) — no changes required

• Delta default OFF: backend applies deltas additively onto a running reconstructed base, but the edge resets per tumbling window → naive enablement double/mis-counts. See docs/delta-baseline-contract.md (Option A; uniform sketch-state-only delta; e2e equality-test gate).
• CMS dims: round cols→pow2 in both Go and Rust so envelopes stay byte-identical (asap_sketchlib ↔ sketchlib-go byte-format harmonization (cross-language parity) #243).
• Sliding stays edge-tumbling. MaxSeries: backend is eventually-consistent.

Rust parity (#243)

Mirrored CMS/CountSketch dim normalization into asap-precompute-rs; B6 OTAP observer keying fixed there too. (Full-state ApplyDelta needed no Rust change — already correct.)

Verification

• Go: build/vet/test green across all three modules (incl. the -race test).
• Rust: cargo build + cargo test (incl. --features otap) green.
• OCB end-to-end: build_asap_otel.sh produced the full asap-otel collector; asap-otel components lists asap_edge. ✅

Related PRs

• fix(cms): fold column index in queryFrequencyFast to match insert (non-pow2 cols) sketchlib-go#60 — CMS queryFrequencyFast column-fold.
• harden(ingest): validate inbound CMS/CountSketch wire dimensions (defensive) ASAPQuery-backend#344 — defensive inbound CMS/CountSketch dim-validation.

Follow-ups (not in this PR)

• Sketch-proto field removal (queued next effort): drop metric count/sum/min/max from all 5 *SketchDataPoints + delta protos; route exact aggregates to controller-provisioned sum/MinMax edge aggregations. Spans proto → sketchlib-go/asap_sketchlib → edge → backend → regenerated asap_sketchlib ↔ sketchlib-go byte-format harmonization (cross-language parity) #243 goldens. Lands before/with delta enablement.
• Delta transmission enablement: implement Option A from docs/delta-baseline-contract.md (edge per-window deltas + backend per-window base rotation; DDSketch first), gated by an e2e delta-ON==delta-OFF equality test; re-establish the asap_sketchlib ↔ sketchlib-go byte-format harmonization (cross-language parity) #243 golden parity harness removed in chore: remove unused integration/ test suite #450.

🤖 Generated with Claude Code

[zzylol]

Companion PRs (both open):

• fix(cms): fold column index in queryFrequencyFast to match insert (non-pow2 cols) sketchlib-go#60 — CMS queryFrequencyFast column-fold (non-pow2 root cause).
• harden(ingest): validate inbound CMS/CountSketch wire dimensions (defensive) ASAPQuery-backend#344 — defensive inbound CMS/CountSketch dim-validation (optional hardening; uses the same rows*ceil(log2(cols))>64 budget as this PR's edge guard).

End-to-end verified: OCB build_asap_otel.sh produced the full asap-otel collector binary with the fixed source pinned via local replace; asap-otel components lists asap_edge.