Pub/sub abstraction: decouple from Pulsar (#751)

Remove Pulsar-specific concepts from application code so that
the pub/sub backend is swappable via configuration.

Rename translators:
- to_pulsar/from_pulsar → decode/encode across all translator
  classes, dispatch handlers, and tests (55+ files)
- from_response_with_completion → encode_with_completion
- Remove pulsar.schema.Record from translator base class

Queue naming (CLASS:TOPICSPACE:TOPIC):
- Replace topic() helper with queue() using new format:
  flow:tg:name, request:tg:name, response:tg:name, state:tg:name
- Queue class implies persistence/TTL (no QoS in names)
- Update Pulsar backend map_topic() to parse new format
- Librarian queues use flow class (persistent, for chunking)
- Config push uses state class (persistent, last-value)
- Remove 15 dead topic imports from schema files
- Update init_trustgraph.py namespace: config → state

Confine Pulsar to pulsar_backend.py:
- Delete legacy PulsarClient class from pubsub.py
- Move add_args to add_pubsub_args() with standalone flag
  for CLI tools (defaults to localhost)
- PulsarBackendConsumer.receive() catches _pulsar.Timeout,
  raises standard TimeoutError
- Remove Pulsar imports from: async_processor, flow_processor,
  log_level, all 11 client files, 4 storage writers, gateway
  service, gateway config receiver
- Remove log_level/LoggerLevel from client API
- Rewrite tg-monitor-prompts to use backend abstraction
- Update tg-dump-queues to use add_pubsub_args

Also: pubsub-abstraction.md tech spec covering problem statement,
design goals, as-is requirements, candidate broker assessment,
approach, and implementation order.

trustgraph-cli/trustgraph/cli/dump_queues.py

@@ -8,8 +8,6 @@ message flows, diagnosing stuck services, and understanding system behavior.
 Uses TrustGraph's Subscriber abstraction for future-proof pub/sub compatibility.
 """
 
-import pulsar
-from pulsar.schema import BytesSchema
 import sys
 import json
 import asyncio
@@ -17,7 +15,7 @@ from datetime import datetime
 import argparse
 
 from trustgraph.base.subscriber import Subscriber
-from trustgraph.base.pubsub import get_pubsub
+from trustgraph.base.pubsub import get_pubsub, add_pubsub_args
 
 def decode_json_strings(obj):
     """Recursively decode JSON-encoded string values within a dict/list."""
@@ -172,15 +170,13 @@ async def log_writer(central_queue, file_handle, shutdown_event, console_output=
                 break
 
 
-async def async_main(queues, output_file, pulsar_host, listener_name, subscriber_name, append_mode):
+async def async_main(queues, output_file, subscriber_name, append_mode, **pubsub_config):
     """
     Main async function to monitor multiple queues concurrently.
 
     Args:
         queues: List of queue names to monitor
         output_file: Path to output file
-        pulsar_host: Pulsar connection URL
-        listener_name: Pulsar listener name
         subscriber_name: Base name for subscribers
         append_mode: Whether to append to existing file
     """
@@ -194,9 +190,9 @@ async def async_main(queues, output_file, pulsar_host, listener_name, subscriber
 
     # Create backend connection
     try:
-        backend = get_pubsub(pulsar_host=pulsar_host, pulsar_listener=listener_name, pubsub_backend='pulsar')
+        backend = get_pubsub(**pubsub_config)
     except Exception as e:
-        print(f"Error connecting to backend at {pulsar_host}: {e}", file=sys.stderr)
+        print(f"Error connecting to backend: {e}", file=sys.stderr)
         sys.exit(1)
 
     # Create Subscribers and central queue
@@ -291,25 +287,20 @@ def main():
         description='Monitor and dump messages from multiple Pulsar queues',
         epilog="""
 Examples:
-  # Monitor agent and prompt queues
-  tg-dump-queues non-persistent://tg/request/agent:default \\
-                 non-persistent://tg/request/prompt:default
+  # Monitor agent and prompt flow queues
+  tg-dump-queues flow:tg:agent-request:default \\
+                 flow:tg:prompt-request:default
 
   # Monitor with custom output file
-  tg-dump-queues non-persistent://tg/request/agent:default \\
+  tg-dump-queues flow:tg:agent-request:default \\
                  --output debug.log
 
   # Append to existing log file
-  tg-dump-queues non-persistent://tg/request/agent:default \\
+  tg-dump-queues flow:tg:agent-request:default \\
                  --output queue.log --append
 
-Common queue patterns:
-  - Agent requests:   non-persistent://tg/request/agent:default
-  - Agent responses:  non-persistent://tg/response/agent:default
-  - Prompt requests:  non-persistent://tg/request/prompt:default
-  - Prompt responses: non-persistent://tg/response/prompt:default
-  - LLM requests:     non-persistent://tg/request/text-completion:default
-  - LLM responses:    non-persistent://tg/response/text-completion:default
+  # Raw Pulsar URIs also accepted
+  tg-dump-queues persistent://tg/flow/agent-request:default
 
 IMPORTANT:
   This tool subscribes to queues without a schema (schema-less mode). To avoid
@@ -340,17 +331,7 @@ IMPORTANT:
         help='Append to output file instead of overwriting'
     )
 
-    parser.add_argument(
-        '--pulsar-host',
-        default='pulsar://localhost:6650',
-        help='Pulsar host URL (default: pulsar://localhost:6650)'
-    )
-
-    parser.add_argument(
-        '--listener-name',
-        default='localhost',
-        help='Pulsar listener name (default: localhost)'
-    )
+    add_pubsub_args(parser, standalone=True)
 
     parser.add_argument(
         '--subscriber',
@@ -371,10 +352,12 @@ IMPORTANT:
         asyncio.run(async_main(
             queues=queues,
             output_file=args.output,
-            pulsar_host=args.pulsar_host,
-            listener_name=args.listener_name,
             subscriber_name=args.subscriber,
-            append_mode=args.append
+            append_mode=args.append,
+            pubsub_backend=args.pubsub_backend,
+            pulsar_host=args.pulsar_host,
+            pulsar_api_key=args.pulsar_api_key,
+            pulsar_listener=args.pulsar_listener,
         ))
     except KeyboardInterrupt:
         # Already handled in async_main