controller: port replan.rs::push_config_to_agent to typed-stage-split pipeline

[zzylol]

Summary

Ports the OpAMP-push side of the agent-config emit to the typed L5
stage-split pipeline so reconnecting (plan-pinned) agents receive
the same routed YAML as fresh-connect agents — finishes the
OpAMP-on-connect side of the typed emit after #329 ported the
bootstrap GET path.

Why

Replanner::push_config_to_agent (and the agent-config push in
replan_metric) called the legacy generate_agent_config emitter,
which produces a single-pipeline DDSketch YAML with no gorillas3
archive write, no OTTL routing processor, and no
metrics/warm_passthrough pipeline. Agents that connected via the
OpAMP on_connect callback (the post-#333 reconnection path) got
that legacy YAML — so freshness-probe routing reached
fresh-connect agents (criterion ⑥ on #46) but NOT plan-pinned
reconnecting agents.

Closes the gap on issue #46, criterion ⑥.

What changed

• replan.rs: new private helpers try_emit_typed_edge_yaml(metric)
  / try_emit_typed_edge_yaml_for_workload(&wl) that mirror
  main::emit_bootstrap_typed's flow (bind_workload_typed →
  split_typed_three_stage → pick Edge → apply demo plumbing →
  emit_for_runtime).
• push_config_to_agent and replan_metric's agent-config push
  branch on planner::stage_split::typed_stage_split_enabled() —
  typed emit on, legacy fallback on emit failure or when the gate
  is off.
• New builder Replanner::with_workload_registry(Arc<WorkloadRegistry>)
  so the typed path can extend its edge config with the same
  archive-tier metrics the bootstrap GET path applies. main()
  wires it during replanner construction.
• config/mod.rs: extracted extend_edge_with_demo_plumbing from
  the inline body of emit_bootstrap_typed. Both bootstrap and
  replan now apply the SAME freshness-probe + workload-registry
  archive extension. main::emit_bootstrap_typed collapses to a
  one-line call.

Gate behaviour

USE_TYPED_STAGE_SPLIT	path
unset / 0	legacy — generate_agent_config (single-pipeline DDSketch). Backwards-compat.
1 / true / yes	typed — bind → stage-split → Edge → demo-plumbing → emit_for_runtime(AsapOtel, …). On error, falls back to the legacy emitter so the push never silently drops.

Same gate / same matrix as handle_plan (#329's PR) and
handle_bootstrap_agent_config.

Runtime default

OpAMP on_connect doesn't surface the agent's X-Agent-Runtime
header today, so the typed emit defaults to
AgentRuntime::AsapOtel — matches the bootstrap default for
unspecified clients. If a future commit threads runtime info
through OpAMP, swap the default for a per-agent lookup.

Test plan

• cargo test --release replan::tests:: — 7/7 pass, including
  the two new tests:
  • typed_replan_emit_includes_freshness_probe_routing —
    asserts the typed YAML contains gorillas3, routing,
    metrics/warm_passthrough, and references the freshness probe.
  • legacy_path_omits_typed_processors_when_gate_off — pins
    the gate semantics so a regression always-on'ing the typed path
    surfaces here.
• cargo build --release
• Demo verification on the OpAMP-on-connect path (out of scope
  for this PR — requires a full demo run).

Pre-existing failing tests in controller/src/main.rs::api_tests
(agent_receives_config_on_connect_via_workload_registry,
replan_pushes_only_to_registered_agent) fail on origin/main too
— unrelated WebSocket protobuf decode race.

🤖 Generated with Claude Code