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-dev/tests/test_agent_build.py

@@ -11,9 +11,9 @@ import httpx
 import pytest
 from test_config import SECRETS, P, tree
 
-from nisse_core.catalog import ModelCatalog, UnknownModel
-from nisse_core.execution import SSHHost
-from nisse_core.llm import AnthropicPassthroughClient, LiteLLMClient
+from nisse_core.execution.ssh import SSHHost
+from nisse_core.models.catalog import ModelCatalog, UnknownModel
+from nisse_core.models.llm import AnthropicPassthroughClient, LiteLLMClient
 from nisse_core.oplog import OpLog
 from nisse_dev.config import AgentConfig
 from nisse_dev.loop.build import RunningLoop, build_loop_agent, discover_models
@@ -143,7 +143,7 @@ def offline(monkeypatch: Any, origins: dict[str, str] | str, catalog=None) -> No
     """Only the network boundaries faked: Gitea, LiteLLM's model list, Matrix."""
     # The proxy here doesn't exist: a call to it fails at once rather than
     # waiting out an outage's backoff (L5).
-    monkeypatch.setattr("nisse_core.llm.OUTAGE_BACKOFF_S", ())
+    monkeypatch.setattr("nisse_core.models.llm.OUTAGE_BACKOFF_S", ())
     monkeypatch.setattr(
         "nisse_dev.loop.build.GiteaClient.whoami", lambda self: "nisse-dev-testing"
     )