deploy(mvp-multinode): activate intchunk cold path + sampling experiment knobs

[zzylol]

Salvages the genuinely-unique, still-applicable experiment config from the stale local branch chore/split-cold-backend-node1 (tip 944e054, snapshotted on the now ~6-PRs-behind base 2939d23). That branch's ~5,300-line WIP is almost entirely already on main via merged PRs, so a direct PR from it would revert merged work. This PR carries only the 3 deploy-config deltas that enable already-merged features not yet turned on in the multinode demo. Config-only: no build required.

Included (each activates a now-on-main feature)

File	Change	Activates
deploy/mvp-multinode/configs/asap/asap-otel-agent-b6-asap-single-sketch.yaml	Add cold.format: intchunk + coldpart_endpoint: .../ingest/coldpart under asap_edge	The intchunk decode-on-read cold path (opt-in, landed via #439/#442). The asapedgeprocessor ColdConfig on main already supports format/coldpart_endpoint (config.go); this enables it in the static reference agent config. shard_count left at main's smooth-flush 12 (NOT reverted to the branch's 4).
deploy/mvp-multinode/configs/asap/mvp-workload.yaml	Add sample_p: 0.5 to the HLL (unique_users_per_min, #6) and CountMinSketch (endpoint_request_freq, #8) families	The fused processor's sampling path (SampleP mapstructure key is already on main; backend rescales x1/p). The workload just activates it.
deploy/mvp-multinode/scripts/run_demo.sh	Add -e ASAP_COLD_FORMAT=intchunk and -e ASAP_AGENT_MEMORY_LIMIT_MIB=8192 to the control-plane container	The controller-emitted (OpAMP) agent config: ASAP_COLD_FORMAT flips the generated cold format to intchunk and ASAP_AGENT_MEMORY_LIMIT_MIB sets the agent memory limit at emit time. Both env knobs are already consumed by the merged control_plane (emit/mod.rs, emit/stage_config.rs).

Total diff: 3 files, +10 lines, additions only. All three files validated (YAML parses, bash -n clean).

Excluded as superseded (NOT carried — would revert merged work)

• All asap-precompute-rs changes — Rust sketchlib migration is already on main (sketches/cms.rs diff vs main = 0 lines).
• asap-gorilla-go coldpart/intchunk/fragment + asap-precompute-go/sketches sampling — merged via feat(intchunk): cold INT best-of-N lossless value chunk codec #434 / feat: coldpart Part format in asap-gorilla-go + agent intchunk cold-part ship path #439 / perf(asapedgeprocessor): accumulate intchunk cold parts per block_duration #442 and the sample_p merge.
• asapedgeprocessor code (coldpart_path.go + tests, config/factory/sketch/processor edits) — written against the pre-refactor(asapedgeprocessor): split god-object files into warm/cold/ingest/flush units #448 god-object layout at otel-arrow-asap/collector/...; main now has the refactor(asapedgeprocessor): split god-object files into warm/cold/ingest/flush units #448 split at opentelemetry-collector-contrib-patch/processor/asapedgeprocessor/ with cold_intchunk_accum.go / cold_intchunk_shipper.go already shipping the intchunk cold path. Superseded.
• topology.env hunks — the branch's raw-buffer default + MAX_BUFFER_PER_SERIES=4096 are already on main; the branch's version is older (still uses pre-rename EXPORTER_* vars + the dropped EXPORTER_RATE knob + the fake-exporter image name). Applying it would revert main's otel-app rename. Nothing unique left.
• Most run_demo.sh hunks — the otel-app rename, data/sketch-persistence mkdir, and the --persistence-* data-plane flags are already on main; the branch's flag-vs-env producer invocation is the stale pre-rename form. Only the two control-plane env knobs above were genuinely new.

Conservative note for reviewer: ASAP_COLD_FORMAT=intchunk (controller-emitted config) and the static format: intchunk in the b6 yaml both express the same intent on their respective config-delivery paths (OpAMP-pushed fused config vs. static reference file). If you only want one activation path, drop whichever you don't use. shard_count is intentionally kept at main's 12.

🤖 Generated with Claude Code

[zzylol]

Closing per review — demo/experiment config knobs (intchunk cold-path activation, sample_p=0.5 on HLL/CMS, agent memory cap) that only activate already-merged features. No capability lost; the WIP snapshot remains on chore/split-cold-backend-node1 if wanted later.