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-core/src/nisse_core/oplog.py

@@ -0,0 +1,33 @@
+"""Structured operational logging (architecture L12).
+
+One JSON object per line to stderr (journald captures it when running as a
+service). Every event carries the fixed envelope: ts, agent, event, task_id,
+cause. Logs are diagnostic, never load-bearing — nothing may read them back
+to derive state.
+"""
+
+import json
+import sys
+from datetime import UTC, datetime
+from typing import Any, TextIO
+
+
+class OpLog:
+    def __init__(self, agent: str, stream: TextIO | None = None) -> None:
+        self.agent = agent
+        # Correlation ID for the enclosing unit of work; the orchestrator sets
+        # it when a unit starts and clears it when the unit ends (L12).
+        self.task_id: str | None = None
+        self._stream = stream if stream is not None else sys.stderr
+
+    def emit(self, event: str, *, cause: str, **fields: Any) -> None:
+        record: dict[str, Any] = {
+            "ts": datetime.now(UTC).isoformat(),
+            "agent": self.agent,
+            "event": event,
+            "task_id": self.task_id,
+            "cause": cause,
+            **fields,
+        }
+        self._stream.write(json.dumps(record) + "\n")
+        self._stream.flush()