feat(token-tracking): add record_interactive_task MCP tool

New tool for capturing ad-hoc work done outside formal workplans.
Finds or creates a persistent 'interactive-<repo>' workstream for the
repo, creates the task, marks it done, and records a token event using
the three-tier logic — all in a single call.

Seeded two example events on interactive-the-custodian:
  - Three-tier token recording on task done (8000/3500)
  - Add record_interactive_task MCP tool (4500/1800)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

mcp_server/server.py

@@ -2222,6 +2222,113 @@ def get_doi_summary() -> str:
     return json.dumps(_get("/repos/doi/summary"), indent=2)
 
 
+# ---------------------------------------------------------------------------
+# Interactive / ad-hoc task recording
+# ---------------------------------------------------------------------------
+
+
+@mcp.tool()
+def record_interactive_task(
+    title: str,
+    repo_slug: str,
+    tokens_in: Optional[int] = None,
+    tokens_out: Optional[int] = None,
+    model: Optional[str] = None,
+    agent: Optional[str] = None,
+    description: Optional[str] = None,
+    session_id: Optional[str] = None,
+) -> str:
+    """Record ad-hoc interactive work as a task with token consumption.
+
+    Finds or creates a persistent 'interactive-<repo>' workstream for the repo,
+    creates the task, marks it done immediately, and records a token event using
+    the three-tier logic (exact > heuristic).
+
+    Use this for work done outside a formal workplan: quick fixes, config changes,
+    code reviews, one-off investigations, or any session work worth tracking.
+
+    Args:
+        title: Short description of the work done
+        repo_slug: Registered repo slug, e.g. 'the-custodian', 'inter-hub'
+        tokens_in: Exact input token count for this task (Tier 1 — best practice)
+        tokens_out: Exact output token count for this task (Tier 1)
+        model: Model identifier, e.g. 'claude-sonnet-4-6'
+        agent: Agent name, e.g. 'custodian', 'ralph'
+        description: Optional longer description of what was done
+        session_id: Agent session identifier
+    """
+    # Resolve repo
+    repos = _get("/repos/")
+    if isinstance(repos, dict) and "error" in repos:
+        return json.dumps(repos)
+    repo = next((r for r in (repos or []) if r.get("slug") == repo_slug), None)
+    if not repo:
+        return json.dumps({"error": f"Repo not found: {repo_slug!r}. Register it first with register_repo()."})
+
+    repo_id = repo["id"]
+    domain_slug = repo.get("domain_slug") or repo.get("domain")
+    ws_slug = f"interactive-{repo_slug}"
+
+    # Find or create the interactive workstream
+    existing = _get("/workstreams/", {"slug": ws_slug})
+    ws = existing[0] if isinstance(existing, list) and existing else None
+
+    if not ws:
+        # Find a topic for this domain to satisfy the FK
+        topics = _get("/topics/")
+        topic = next(
+            (t for t in (topics if isinstance(topics, list) else [])
+             if t.get("domain_slug") == domain_slug or t.get("domain") == domain_slug),
+            None,
+        )
+        if not topic:
+            return json.dumps({"error": f"No topic found for domain {domain_slug!r} — cannot create workstream."})
+
+        ws = _post("/workstreams", {
+            "topic_id": topic["id"],
+            "slug": ws_slug,
+            "title": f"Interactive — {repo_slug}",
+            "description": "Ad-hoc tasks created outside a formal workplan.",
+            "owner": "custodian",
+            "repo_id": repo_id,
+        })
+        if "error" in ws:
+            return json.dumps(ws)
+
+    # Create task
+    task = _post("/tasks", {
+        "workstream_id": ws["id"],
+        "title": title,
+        "description": description,
+        "priority": "medium",
+    })
+    if "error" in task:
+        return json.dumps(task)
+
+    # Mark done — triggers three-tier token recording in the router
+    body: dict[str, Any] = {
+        "status": "done",
+        "model": model,
+        "agent": agent,
+        "session_id": session_id,
+    }
+    if tokens_in is not None:
+        body["tokens_in"] = tokens_in
+    if tokens_out is not None:
+        body["tokens_out"] = tokens_out
+
+    _patch(f"/tasks/{task['id']}", body)
+
+    tier = "exact" if tokens_in is not None else "heuristic"
+    return json.dumps({
+        "task_id": task["id"],
+        "workstream_id": ws["id"],
+        "workstream_slug": ws_slug,
+        "title": title,
+        "token_tier": tier,
+    }, indent=2)
+
+
 # ---------------------------------------------------------------------------
 # Token events
 # ---------------------------------------------------------------------------