refactor(#3309): extract health-diagnostic-types leaf module, wire RULES

Wiring all 8 rule-group files into health-diagnostic.cts's RULES array
created a genuine CJS circular dependency: each group file required
health-diagnostic.cjs back for the shared enums, and health-diagnostic.cjs
now required the group files forward, so the enums were undefined
mid-load (destructuring health-diagnostic.cjs's still-unassigned
exports).

Fixes it by splitting the enums/types (SEVERITY, REMEDY_ACTION,
REMEDY_RISK, Remedy, Diagnostic, Rule) into a dependency-free leaf
module, health-diagnostic-types.cts, that both sides import instead of
each other. health-diagnostic.cts re-exports the enums for existing
consumers. RULES is now the real concatenation of all 8 groups (31
codes — E001 intentionally stays a pre-check outside the table).

docs/INVENTORY-MANIFEST.json

@@ -378,6 +378,7 @@
       "graphify.cjs",
       "gsd2-import.cjs",
       "handshake-serialized.cjs",
+      "health-diagnostic-types.cjs",
       "health-diagnostic.cjs",
       "hook-bus.cjs",
       "host-integration-sdk.cjs",