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

scripts/e2e-cleanup.sh

@@ -11,7 +11,7 @@ if [ -f .env ]; then set -a; . ./.env; set +a; fi
 exec uv run python - "$@" <<'PY'
 import os, sys
 from datetime import datetime, timedelta, timezone
-from nisse_dev.gitea import GiteaClient
+from nisse_core.gitea import GiteaClient
 
 gitea = GiteaClient("https://gitea.dongar.net", os.environ["NISSE_OPERATOR_TOKEN"])
 cutoff = datetime.now(timezone.utc) - (timedelta(0) if "--all" in sys.argv else timedelta(days=1))