chore(road-editor): plan direct-edit task tree and add client test infra

Planning: parent design.md becomes the single authoritative contract
(constraint model with 6 kinds, handle manifest, coordinate/unit
layering, preview sequencing, storage layout and lazy migration, area
config snapshot, API contract). Work is split into four independently
verifiable child tasks with per-step gates and rollback points.

Test infra: pin vitest 4.1.11, add test:client:unit for client pure
logic, extend prettier globs to root *.ts so vitest.config.ts is checked.

Add .gitignore: the repo had none, so inputs/, outputs/, workbench-data/
and the client build output were untracked rather than ignored.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.trellis/tasks/08-26-direct-edit-solver-api/task.json

@@ -0,0 +1,26 @@
+{
+  "id": "direct-edit-solver-api",
+  "name": "direct-edit-solver-api",
+  "title": "约束求解器与编辑 API",
+  "description": "resolveDirectEditConstraints 纯函数边界，以及预览/保存/revision/rebase API",
+  "status": "planning",
+  "dev_type": null,
+  "scope": null,
+  "package": null,
+  "priority": "P2",
+  "creator": "dingkang",
+  "assignee": "dingkang",
+  "createdAt": "2026-08-26",
+  "completedAt": null,
+  "branch": null,
+  "base_branch": "main",
+  "worktree_path": null,
+  "commit": null,
+  "pr_url": null,
+  "subtasks": [],
+  "children": [],
+  "parent": "08-26-direct-manipulation-road-editor",
+  "relatedFiles": [],
+  "notes": "",
+  "meta": {}
+}