M7.1: extract nisse-core

What isn't the dev agent's moves to nisse-core, unchanged in behaviour,
with its tests: canonical, render, render_anthropic, llm, catalog, probe,
context, views, state, reconcile, worker, cancel, dump, transport, matrix,
execution, testing, vault, memory, oplog, envfile and gitea (whole).

- nisse_core.state.StateStore holds the tables every agent has; an
  agent's subclass adds its tables (version, migrations), roles and
  views. nisse_dev.state.StateStore adds the build VM blocks (v5).
- views.project takes what each role is shown, rather than a fixed table.
- Vault takes the agent's name (agent=), for provenance.
- A test that nisse_core never imports an agent.
- The loop, config, git, delegation, expert, tools and evals stay in
  nisse-dev until nisse-ops has a loop to share.

Docs: the Development Plan marks M7.1 done and notes that Phase 6 waits on
the agent host and Terraform; Architecture Part L names the package.

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

nisse-dev/tests/test_loop_milestones.py

@@ -10,11 +10,10 @@ from typing import Any
 import pytest
 from model_contract import assert_renderable
 
-from nisse_dev.cancel import Cancel
-from nisse_dev.canonical import ToolCall
-from nisse_dev.execution import SSHHost
-from nisse_dev.git import GitRepo
-from nisse_dev.gitea import (
+from nisse_core.cancel import Cancel
+from nisse_core.canonical import ToolCall
+from nisse_core.execution import SSHHost
+from nisse_core.gitea import (
     Approval,
     Comment,
     GiteaError,
@@ -22,15 +21,16 @@ from nisse_dev.gitea import (
     PullRequest,
     ReviewNote,
 )
+from nisse_core.oplog import OpLog
+from nisse_core.transport import InMemoryTransport
+from nisse_core.worker import InlineWorker
+from nisse_dev.git import GitRepo
 from nisse_dev.loop.agent import LoopAgent
 from nisse_dev.loop.driver import Driver
 from nisse_dev.loop.items import ANSWER, MERGE, WAITING, loop_of
 from nisse_dev.loop.milestones import OPEN_PR, Milestones
-from nisse_dev.oplog import OpLog
 from nisse_dev.state import StateStore
 from nisse_dev.tools import Workspace
-from nisse_dev.transport import InMemoryTransport
-from nisse_dev.worker import InlineWorker
 
 DON = "@don:test"