Add durable search event indexing contract

src/govoplan_core/core/search.py

@@ -5,6 +5,7 @@ from dataclasses import dataclass, field
 from datetime import datetime
 from typing import Literal, Protocol, runtime_checkable
 
+from govoplan_core.core.events import PlatformEvent
 from govoplan_core.core.external_references import ExternalObjectReference
 from govoplan_core.core.modules import ModuleContext
 
@@ -379,6 +380,43 @@ class SearchSourceProvider(Protocol):
         """Return an explicit decision for every requested reference key."""
 
 
+@runtime_checkable
+class SearchEventSourceProvider(Protocol):
+    """Optional source extension for committed, idempotent index deltas."""
+
+    def index_changes_for_event(
+        self,
+        session: object,
+        *,
+        event: PlatformEvent,
+        delivery_key: str,
+    ) -> Sequence[SearchIndexChange]:
+        """Translate one committed event into authoritative index changes."""
+
+
+@runtime_checkable
+class SearchIndexCoordinator(Protocol):
+    """Worker-facing orchestration surface exposed by the Search module."""
+
+    def ingest_event(
+        self,
+        session: object,
+        *,
+        event: PlatformEvent,
+        delivery_key: str,
+    ) -> Mapping[str, int]:
+        ...
+
+    def process_changes(
+        self,
+        session: object,
+        *,
+        limit: int = 100,
+        tenant_id: str | None = None,
+    ) -> Mapping[str, int]:
+        ...
+
+
 SearchProviderFactory = Callable[[ModuleContext], SearchProvider]
 SearchSourceProviderFactory = Callable[
     [ModuleContext],
@@ -455,8 +493,10 @@ __all__ = [
     "SearchBackfillRequest",
     "SearchContextKind",
     "SearchDocument",
+    "SearchEventSourceProvider",
     "SearchIndexChange",
     "SearchIndexChangeKind",
+    "SearchIndexCoordinator",
     "SearchIndexWriter",
     "SearchProvider",
     "SearchProviderFactory",