docs: bring the documentation up to the daemon/client era

A large gap had opened between the docs and the code: the README and
INTEGRATION guide did not mention the gRPC daemon or the Python client at
all (the entire vendor surface), ARCHITECTURE still described secs_server
as the ~1200-line canonical wiring example (it is a ~110-line thin main
over EquipmentRuntime), and test counts across six files were stale
(445/2753 -> 473/3087 core + the separate 125-assertion daemon suite).

- README: new "Integrating your tool (pick a tier)" section — Python
  client / any-language gRPC / embedded C++ — plus daemon tests and
  tools/run_interop.sh in the Testing section.
- ARCHITECTURE: layer diagram gains the vendor-surface and
  EquipmentRuntime/default_handlers tiers; stale wiring row fixed.
- INTEGRATION: three-tier chooser up front (this guide = the C++ tier).
- ch30 tour: secs_gemd + secs_gemd_tests in the binaries table.
- ch31: example alarm used a nonexistent `alcd:` field with bit 7 set
  (which the validator forbids) -> real `category:`/`name:` fields, and
  the roles: block documented.
- ch35: handler-location note now points at default_handlers.cpp's 15
  per-capability register_* functions.
- ch40: built-artifacts list + sample output counts.
- ch50: secsgem::gem runtime/default_handlers/handler_slot/name_index
  includes + new secsgem::daemon namespace section.
- PROOFS: test-count table gains the runtime/handlers/daemon row so the
  tally adds up; daemon suite noted. VERIFICATION/COMPLIANCE counts.
- interop/README: the one-command runner + the two daemon-track harnesses
  (daemon_interop, pyclient_interop).

Audited via a docs-vs-code sweep (the audit itself under-reported: it
validated counts textually; reality was 473/3087).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/31_spec_as_data_and_codegen.md

@@ -134,11 +134,21 @@ ceids:
   - {id: 300, name: ProcessStarted}
 
 alarms:
-  - {id: 1, alcd: 0x84, text: "Chamber pressure above threshold"}
+  # `category` is the lower-7 ALCD severity bitmap; bit 7 (set/clear) is
+  # applied at emit time and must NOT be in YAML. `name` is an optional
+  # local key for name-based APIs (the gRPC daemon / Python client).
+  - {id: 1, name: pressure_high, category: 4,
+     text: "Chamber pressure above threshold"}
 
 host_commands:
   - {name: START, ack: Accept, emit_ceid: 300}
   - {name: FAULT, ack: Accept, set_alarm: 1}
+
+# Role bindings: which of the ids above the engine's built-in behaviours
+# target (control-state/clock SVID refresh, CJ state CEIDs).
+roles:
+  control_state_svid: 1
+  clock_svid: 2
 ```
 
 Loaded at startup by `config::load_equipment`.  Every key under