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

scripts/benchmark.py

@@ -14,8 +14,8 @@ import os
 import sys
 from pathlib import Path
 
-from nisse_core.catalog import ModelCatalog
 from nisse_core.envfile import load_env_file
+from nisse_core.models.catalog import ModelCatalog
 from nisse_dev.bench.results import append, load, render, results_file, summarise
 from nisse_dev.bench.runner import agent_commit, run_task
 from nisse_dev.bench.tasks import load_tasks