fix: resume distributed task ID counter past existing IDs; extract plugin view types

The dashboard task-create route now uses the distributed task ID allocator
(FN-3450). On projects whose tasks had been allocated through the legacy
config.nextId counter, the allocator's `ensureStateRow` was seeding a fresh
prefix at sequence 1, so new tasks restarted at FN-001 even when FN-3700
already existed. ensureStateRow now seeds past:

- the legacy config.nextId counter (when configured taskPrefix matches), and
- one past the highest numeric suffix on any existing tasks/archivedTasks row
  for the prefix.

A regression test seeds FN-3700 in a fresh DB and asserts the next reservation
returns FN-3701, not FN-001.

Plugin dashboard view contracts are now exposed via a slim type-only module
(`@fusion/dashboard/app/plugins/types`). External plugin tsc builds previously
imported `pluginViewRegistry`, transitively pulling in dashboard runtime
sources (React components, CSS, lucide-react). The dependency-graph plugin's
import + path mapping is updated to use the new module.

Schema housekeeping: drop unused scaffolding tables left over from an earlier
migration via a new idempotent migration (v67). Fresh DBs see no change;
existing DBs that ran the older migration get the orphan tables dropped on
next init.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

plugins/fusion-plugin-dependency-graph/src/index.ts

@@ -1,5 +1,5 @@
 import type { Task, TaskDetail, WorkflowStep } from "@fusion/core";
-import type { PluginDashboardViewContext } from "@fusion/dashboard/app/plugins/pluginViewRegistry";
+import type { PluginDashboardViewContext } from "@fusion/dashboard/app/plugins/types";
 import { definePlugin } from "@fusion/plugin-sdk";
 import { createElement } from "react";
 import { DependencyGraph } from "./DependencyGraph";