feat: add durable Core Hub absorption runtime

hub_core/runtime/config.py

@@ -11,6 +11,10 @@ def _env_bool(name: str, default: bool) -> bool:
     return raw.strip().lower() in {"1", "true", "yes", "on"}
 
 
+def _env_set(name: str) -> frozenset[str]:
+    return frozenset(value.strip() for value in os.getenv(name, "").split(",") if value.strip())
+
+
 @dataclass(frozen=True, slots=True)
 class RuntimeSettings:
     environment: str = "development"
@@ -23,6 +27,21 @@ class RuntimeSettings:
     mcp_port: int = 8011
     mcp_transport: str = "http"
     database_url: str | None = None
+    api_token: str | None = None
+    v2_groups: frozenset[str] = frozenset()
+    v2_write_groups: frozenset[str] = frozenset()
+    legacy_write_groups: frozenset[str] = frozenset()
+    legacy_health: bool = False
+
+    def __post_init__(self) -> None:
+        overlap = self.v2_write_groups & self.legacy_write_groups
+        if overlap:
+            joined = ", ".join(sorted(overlap))
+            raise ValueError(f"hub-core and Core Hub write groups overlap: {joined}")
+        unknown = self.v2_write_groups - self.v2_groups
+        if unknown:
+            joined = ", ".join(sorted(unknown))
+            raise ValueError(f"hub-core write groups are not enabled: {joined}")
 
     @classmethod
     def from_env(cls) -> RuntimeSettings:
@@ -41,6 +60,11 @@ class RuntimeSettings:
             mcp_port=int(os.getenv("HUB_CORE_MCP_PORT", "8011")),
             mcp_transport=os.getenv("HUB_CORE_MCP_TRANSPORT", "http"),
             database_url=os.getenv("HUB_CORE_DATABASE_URL") or os.getenv("DATABASE_URL"),
+            api_token=os.getenv("HUB_CORE_API_TOKEN") or os.getenv("CORE_HUB_API_TOKEN"),
+            v2_groups=_env_set("HUB_CORE_V2_GROUPS"),
+            v2_write_groups=_env_set("HUB_CORE_V2_WRITE_GROUPS"),
+            legacy_write_groups=_env_set("CORE_HUB_V2_WRITE_GROUPS"),
+            legacy_health=_env_bool("HUB_CORE_LEGACY_HEALTH", False),
         )
 
     def readiness_checks(self, store_backend: str) -> dict[str, str]:
@@ -51,6 +75,9 @@ class RuntimeSettings:
             "active_backend": store_backend,
             "ephemeral_backend": "allowed" if ephemeral_allowed else "not_allowed",
             "contract": "helixforge.hub-extension/0.1.0",
+            "v2_groups": ",".join(sorted(self.v2_groups)) or "none",
+            "v2_write_groups": ",".join(sorted(self.v2_write_groups)) or "none",
+            "legacy_write_groups": ",".join(sorted(self.legacy_write_groups)) or "none",
         }
 
     def is_ready(self, store_backend: str) -> bool: