feat: data store replication configuration and TLS upgrade

- Add centralised qdrant_config.py helper with env-var fallback for
  QDRANT_URL, QDRANT_API_KEY, QDRANT_REPLICATION_FACTOR, QDRANT_SHARD_NUMBER
- Update all 6 Qdrant processors to use the helper; writers pass
  replication_factor and shard_number to create_collection
- Fix hardcoded Cassandra replication_factor=1 in cassandra_kg.py,
  write.py, and sparql_cassandra.py to respect CASSANDRA_REPLICATION_FACTOR
- Upgrade Cassandra TLS from deprecated PROTOCOL_TLSv1_2 to
  ssl.create_default_context() across all connectors

trustgraph-base/trustgraph/base/qdrant_config.py

@@ -0,0 +1,87 @@
+
+import os
+import argparse
+from typing import Optional, Any, Tuple
+
+
+def get_qdrant_defaults() -> dict:
+    return {
+        'url': os.getenv('QDRANT_URL', 'http://localhost:6333'),
+        'api_key': os.getenv('QDRANT_API_KEY'),
+        'replication_factor': int(os.getenv('QDRANT_REPLICATION_FACTOR', '1')),
+        'shard_number': int(os.getenv('QDRANT_SHARD_NUMBER', '1')),
+    }
+
+
+def add_qdrant_args(parser: argparse.ArgumentParser) -> None:
+    defaults = get_qdrant_defaults()
+
+    url_help = f"Qdrant URL (default: {defaults['url']})"
+    if 'QDRANT_URL' in os.environ:
+        url_help += " [from QDRANT_URL]"
+
+    api_key_help = "Qdrant API key"
+    if defaults['api_key']:
+        api_key_help += " (default: <set>)"
+        if 'QDRANT_API_KEY' in os.environ:
+            api_key_help += " [from QDRANT_API_KEY]"
+
+    replication_help = f"Qdrant collection replication factor (default: {defaults['replication_factor']})"
+    if 'QDRANT_REPLICATION_FACTOR' in os.environ:
+        replication_help += " [from QDRANT_REPLICATION_FACTOR]"
+
+    shard_help = f"Qdrant collection shard number (default: {defaults['shard_number']})"
+    if 'QDRANT_SHARD_NUMBER' in os.environ:
+        shard_help += " [from QDRANT_SHARD_NUMBER]"
+
+    parser.add_argument(
+        '--store-uri',
+        default=defaults['url'],
+        help=url_help,
+    )
+
+    parser.add_argument(
+        '--api-key',
+        default=defaults['api_key'],
+        help=api_key_help,
+    )
+
+    parser.add_argument(
+        '--qdrant-replication-factor',
+        type=int,
+        default=defaults['replication_factor'],
+        help=replication_help,
+    )
+
+    parser.add_argument(
+        '--qdrant-shard-number',
+        type=int,
+        default=defaults['shard_number'],
+        help=shard_help,
+    )
+
+
+def resolve_qdrant_config(
+    args: Optional[Any] = None,
+    url: Optional[str] = None,
+    api_key: Optional[str] = None,
+    replication_factor: Optional[int] = None,
+    shard_number: Optional[int] = None,
+) -> Tuple[str, Optional[str], int, int]:
+    if args is not None:
+        url = url or getattr(args, 'store_uri', None)
+        api_key = api_key or getattr(args, 'api_key', None)
+        replication_factor = replication_factor or getattr(
+            args, 'qdrant_replication_factor', None
+        )
+        shard_number = shard_number or getattr(
+            args, 'qdrant_shard_number', None
+        )
+
+    defaults = get_qdrant_defaults()
+    url = url or defaults['url']
+    api_key = api_key or defaults['api_key']
+    replication_factor = replication_factor or defaults['replication_factor']
+    shard_number = shard_number or defaults['shard_number']
+
+    return url, api_key, replication_factor, shard_number