feat: add type hints to all public functions in trustgraph/base (#803)

feat: add type hints to all public functions in trustgraph/base

Add type annotations to 23 modules covering:
- Metrics classes (ConsumerMetrics, ProducerMetrics, etc.)
- Spec classes (ConsumerSpec, ProducerSpec, SubscriberSpec, etc.)
- Service classes with add_args() and run() methods
- Utility functions (logging, pubsub, clients)
- AsyncProcessor methods

All 93 public functions now fully typed.

Refs #785

* refactor: deduplicate imports and move __future__ after docstrings

Addresses review feedback on PR #803:
- Remove duplicate 'from argparse import ArgumentParser' across 12 files
- Move 'from __future__ import annotations' to line 1 in all files
- Clean up excessive blank lines

trustgraph-base/trustgraph/base/document_embeddings_query_service.py

@@ -1,3 +1,6 @@
+from __future__ import annotations
+
+from argparse import ArgumentParser
 
 """
 Document embeddings query service.  Input is vectors.  Output is list of
@@ -82,7 +85,7 @@ class DocumentEmbeddingsQueryService(FlowProcessor):
             await flow("response").send(r, properties={"id": id})
 
     @staticmethod
-    def add_args(parser):
+    def add_args(parser: ArgumentParser) -> None:
 
         FlowProcessor.add_args(parser)
 
@@ -93,7 +96,7 @@ class DocumentEmbeddingsQueryService(FlowProcessor):
             help=f'Number of concurrent requests (default: {default_concurrency})'
         )
 
-def run():
+def run() -> None:
 
     Processor.launch(default_ident, __doc__)