Retire the collector-facing emission pipeline

[zzylol]

#703 item 18, final deletion step. Stacked on #718 → #715 → #713 — review those first.

−22,510 / +607. control_plane goes from ~51k lines to 29,070; main.rs from 3,500+ to 1,108.

Why this lands as one commit

With the legacy planning endpoints gone (#718), the only remaining entry into the collector config chain was GET /api/v1/collector-config/agent, the HTTP config provider for collector bootstrap. Removing it retires the whole chain, because every part exists to serve that entry:

workloads.yaml startup pre-population
  → Analyzer / DeploymentPlanCompiler
  → PlanStore / WorkloadStore
  → Replanner (expiry + SLA-violation + backend-repost tickers)
  → Scraper (SLA violation detection)
  → OpAMP on-connect / on-disconnect hooks
  → colored_dag stage allocation + three-stage split
  → per-runtime YAML/TOML emitters

Splitting it would leave intermediate states that do not compile.

Deleted

	lines
emit/stage_config.rs	7,410
physical/colored_dag/	2,572
replan.rs	1,350
emit/backend_push.rs	1,043
physical/workload_planner.rs	980
pipeline.rs	843
deployment_cost/{delta,sketch_capability} + scoring	~1,500
emit/{agent,otap,telegraf}.rs	1,857
store/, monitor/, physical/{plan_cache,stage_split,topology}.rs	~1,600
plus the tests covering them	~3,400

Also gone: the USE_TYPED_STAGE_SPLIT kill switch (#703 item 12) — its "off" branch was the legacy emitter; RealizationProvider::stages (item 10), which had no callers; physical/topology.rs (item 11), a pure re-export.

Extracted, not deleted

Two pieces the ASAPPlanner path depends on:

• physical::backend_stage (87 lines) keeps BackendStageConfig, BackendAggregation, BackendReadout, AggregationInput. PhysicalCompiler builds these; backend_plan::from_stage_config consumes them. Their collector-side neighbours (EdgeStageConfig, GatewayStageConfig, ExportTarget, StageId) do not come along.
• emit::backend_wire (419 lines) keeps the storage-routing classifier and build_backend_aggregation_json. That builder stays the single source of the aggregation wire shape, so BackendPlan materializations and the JSON format keep one PolicyFingerprint identity space — the invariant from_stage_config's module doc calls load-bearing.

deployment_cost keeps only what still has consumers: online (behind /api/v1/cost-model), tco (behind /api/v1/tco), wire (post-ASAP cost model). SketchCosts and the benchmark table move into online, its only remaining caller.

Behaviour change

/metrics no longer exposes asap_active_plan_id. The gauge read PlanStore, which was legacy plan history and is gone. Every other asap_runtime_* gauge is unchanged.

Resulting surface

Production routes are now the ASAPPlanner path only:

/api/v1/physical-plan/cost-manifests
/api/v1/metricsql/physical-plan/cost-manifests
/api/v1/physical-plan/compile-and-publish
/api/v1/metricsql/physical-plan/compile-and-publish
/api/v1/clickhouse-plan/compile-and-publish
/api/v1/cost-model
/api/v1/tco
/metrics

AppState is down to opamp, online_store, runtime_samples, active_summary_catalog, backend_client. OpampServer is constructed bare and retains only publish_collector_plans, which the physical path uses.

Testing

• cargo +1.98.0 check -p control_plane --all-targets — clean, no warnings.
• cargo +1.98.0 test -p control_plane --lib — 387 passed, 0 failed (705 → 387; the 318 covered deleted code).
• cargo +1.98.0 test -p data_plane --lib — 1193 passed, 0 failed, unchanged.

🤖 Generated with Claude Code

[zzylol]

Superseded. main moved substantially while this was open (#712, #714, #717 — the last renamed PhysicalCompiler, BackendLocalPlanningSnapshot, compile, planning_request and aggregation_configs), and re-applying the deletion on the current tree was cleaner than replaying this branch through rename-heavy conflicts. Replacement: refactor/703-collector-emit-v2.