Task: One per-config control-plane keyed by config_id, server-side resolution

One per-config start/stop/list control-plane for every asset class, keyed by config_id: the client sends the config_id, the server resolves the config, its children, and the refdata context, checks permissions, and starts the producer via the factory. The FX client-supplied-params pass-through (the no-auth anti-pattern) is deleted.

• One start/stop/list handler serves both kinds, keyed by config_id, resolved server-side with permission checks — the IR curve pattern applied uniformly.
• market_feed_config_handler (client-supplied params, no auth) is deleted; its consumers use the config_id path.
• The NATS protocol carries one request/response shape per verb, kind-agnostic.
• Missing config, disabled config, and vintage-data-missing are reported the same way for both kinds.

One kind-agnostic per-config control-plane replaces the two per-kind handlers: the client sends config_id, the server resolves the config, its children, and the refdata context, checks permissions, and starts the producer via the factory. The FX client-supplied-params pass-through (no auth) is deleted. validate is deleted with it — Qt's Validate Vintage moves to get_vintage_validity, which already serves both kinds.

1. One protocol: new ores.synthetic.api/messaging/feed_config_protocol.hpp (ores::synthetic::messaging) carries the three per-config verbs, kind-agnostic — start_feed_request{config_id}, stop_feed_request{config_id, source_name}, list_feeds_request{} — on subjects =synthetic.v1.feed_configs.start|stop|list. The per-kind structs are deleted with their headers (ir_curve_feed_config_protocol.hpp deleted; market_feed_config_protocol.hpp keeps the folder cascade and vintage-validity shapes and feed_kind_counts, dropping its per-config start/stop/list/validate structs).
2. One handler: feed_config_handler.hpp replaces market_feed_config_handler.hpp and ir_curve_feed_config_handler.hpp (both deleted). It applies the IR pattern uniformly: auth via make_request_context; resolution probes the FX repository first, then the IR repository, by config_id — the market_data_generation_config container has no kind discriminator, so the probe is the resolution. The resolved kind picks the permission check (synthetic::fx_spot_generation_configs:read vs synthetic::ir_curve_generation_configs:read), the enabled gates (config + container), the children reads, and the factory build input. Start dispatches through make_default_feed_factory().make (IR via with_system_tenant + build_ir_curve_refdata_context); the IR builder's vintage_data_missing_error (FX does not throw it) is caught with the uniform vintage-data-missing message. Stop resolves config_id to source_name and calls ctrl_->stop(); list is ctrl_->list() with an empty kind — every running feed, both kinds.
3. Uniform error shape: missing config ("Feed config not found: <id>"), disabled ("Feed config is not enabled: <id>"), already running, qualifier conflict (with the holding source name), and vintage-data-missing read the same for both kinds.
4. Consumers migrate to the config_id path: the registrar subscribes 3 subjects (7 gone); Qt MarketSimulatorWindow sends the unified requests for FX pairs and IR curves (its two list calls merge into one; its per-row FX Validate Vintage loop moves to get_vintage_validity, dropping resolved_price); ores.shell start_feed drops the client-side GMM parameter assembly and sends config_id (stop_feed likewise); tenant_handler IR provisioning sends the unified start request (subject change).
5. Tests: feed_config_handler_tests.cpp mirrors the folder-cascade integration test (real NATS + scoped DB + per-run tenant + test-scoped subjects): seed a container with an FX config and an IR config plus children and refdata; verify start (both kinds), already-running, not-found, disabled, missing children, list, and stop. Registered in tests/component_files.cmake.

Manual QA scenarios (scaffolded via compass add test_scenario, run through the QA Validation Runner panel) that verify this task. Link new ones here as they're created; the scenario doc itself links back via its "Verifies task" field.

Shipped: one kind-agnostic per-config control plane.

• New ores::synthetic::messaging protocol (feed_config_protocol.hpp) with one request/response shape per verb on synthetic.v1.feed_configs.start|stop|list: start_feed_request{config_id}, stop_feed_request{config_id, source_name}, list_feeds_request{}; the per-kind start/validate/ stop/list structs are deleted from market_feed_config_protocol.hpp (folder cascade and vintage-validity shapes stay) and ir_curve_feed_config_protocol.hpp is deleted.
• One feed_config_handler serves both kinds: auth via make_request_context; kind resolution probes the FX repository first, then the IR repository, by config_id (the container has no kind discriminator); the resolved kind picks its permission check, the config+container enabled gates, the children reads, and the factory build input (IR via with_system_tenant + build_ir_curve_refdata_context). Missing, disabled, already-running, qualifier-conflict (naming the holding source_name), and vintage-data-missing read the same for both kinds. Stop resolves config_id to source_name (idempotent counts); list returns every running source_name, gated on both read permissions.
• market_feed_config_handler (client-supplied params, no auth) and ir_curve_feed_config_handler are deleted; the registrar subscribes the 3 unified subjects (7 gone). Consumers migrated: Qt MarketSimulatorWindow (pair and IR loops send config_id; the two list calls merge; FX Validate Vintage moved to get_vintage_validity, dropping resolved_price), ores.shell start/stop feed (GMM assembly and the no-price-model check move server-side), and tenant_handler provisioning.
• Integration tests feed_config_handler_tests.cpp cover start of both kinds by config_id, already-running, not-found and disabled (uniform messages), per-kind permission rejection (X-Error: forbidden), missing-children rejection, the qualifier-conflict report, list gated on both permissions, and stop by config_id or source_name.

Acceptance met. Verification: full build green; the synthetic service component test green (296 assertions, 45 test cases, incl. the 6 new feed_config cases); rat green (exit 0) on a recreated database with all services up — the first rat attempt failed only on pre-existing iam.core repository tests writing deterministic faker names into the shared system tenant (rows left by an earlier rat run); a DB recreate (no schema change) restored the clean state and the rat passed.