nisse-core: group modules into packages by architecture section

A pure move; behaviour unchanged.

- models (L9, L7): llm, catalog, probe, render, render_anthropic, context
- log (L7, L6): canonical, views
- state (L8): store (was state), reconcile, worker, cancel, dump
- knowledge (L10, L6.4): vault, memory
- conversation (L5): transport, matrix
- execution (L13): ssh (was execution), testing
- authority (P3, P4, L4): actions
- gitea, oplog, envfile stay at the top until each gains a second module.

Every import, monkeypatch target, script and doc reference rewritten.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J5Utyfzw7gF7UhjRDEtjTk

nisse-core/tests/test_matrix.py

@@ -4,8 +4,8 @@ import threading
 import httpx
 import pytest
 
-from nisse_core.matrix import MatrixConfig, MatrixTransport, TransportError
-from nisse_core.transport import InboundMessage
+from nisse_core.conversation.matrix import MatrixConfig, MatrixTransport, TransportError
+from nisse_core.conversation.transport import InboundMessage
 
 CONFIG = MatrixConfig(
     homeserver="https://matrix.test",
@@ -349,7 +349,7 @@ def test_a_reply_to_the_operators_own_threaded_message_joins_the_thread() -> Non
 
 
 def test_in_memory_transport_plays_threads() -> None:
-    from nisse_core.transport import InMemoryTransport
+    from nisse_core.conversation.transport import InMemoryTransport
 
     transport = InMemoryTransport()
     seen: list[InboundMessage] = []