Task: Generate sub-registrars for all refdata entities

Run the nats-sub-registrar codegen profile over the refdata-cpp component to emit a <entity>_registrar.hpp/cpp pair for every refdata entity that has a NATS handler. These are consumed by the top-level registrar.cpp in the next task.

• nats-sub-registrar profile run over refdata-cpp; a <entity>_registrar.hpp/cpp pair generated per entity that has a handler, under ores.refdata/core/{include,src}/.../messaging/.
• Every generated registrar references only symbols that exist: handler ctor, handler methods (list/save/remove/history), and protocol request subjects — verified statically.
• Entities without a history protocol carry no_history so the registrar skips the history subscription.
• Entities without a NATS handler are excluded (no registrar) and the gap is captured in the backlog.
• No CMakeLists edits required (src/ is GLOB_RECURSE).

1. Dry-run compass codegen regenerate --component refdata-cpp --profile nats-sub-registrar to confirm output paths.
2. Generate for real (28 domain_entity models; table/junction types are skipped by the profile's model_types filter).
3. Static cross-check each registrar against its handler + protocol.
4. Fix mismatches:
   • currency, counterparty_identifier, party_identifier have no history protocol → add :no_history: true to their C++ ** Flags drawer and regenerate (flag lifts onto the domain_entity context via org_loader and is read by {{^no_history}}).
   • counterparty_contact_information, party_contact_information have no handler header → delete their generated registrars; file a backlog capture for the missing handler decision.
5. Confirm all remaining registrars are fully satisfied.

Generated 26 <entity>_registrar.hpp/cpp pairs under ores.refdata/core/{include,src}/ores.refdata.core/messaging/ via the nats-sub-registrar profile. table and junction models are skipped by the profile's model_types filter (the 14 "incompatible" log lines are expected, not failures).

Five entities needed special handling:

• currency, counterparty_identifier, party_identifier — no history protocol; added :no_history: true to their C++ ** Flags drawer and regenerated, so their registrars wire list/save/remove only.
• counterparty_contact_information, party_contact_information — no generated handler header, so a registrar cannot reference a handler type. Excluded (registrars deleted). Captured for follow-up: doc/agile/product_backlog/inbox/the_nats_sub_registrar_codegen_profile_excludes_co.org.

All 26 registrars were statically cross-checked: every referenced handler ctor, handler method (list/save/remove/history) and protocol request subject exists. No CMakeLists changes were needed (src/ is GLOB_RECURSE). Not yet compiled — the build is exercised when the top-level registrar wires these in (next task). Committed in ea0e4c334.