ticket: start worker runtime execution boundary

.yoi/tickets/00001KW55B32Y/item.md

@@ -2,7 +2,7 @@
 title: 'worker-runtimeにWorker実行Backend境界を追加する'
 state: 'inprogress'
 created_at: '2026-06-27T18:26:46Z'
-updated_at: '2026-06-27T19:08:06Z'
+updated_at: '2026-06-27T19:09:41Z'
 assignee: null
 queued_by: 'workspace-panel'
 queued_at: '2026-06-27T19:06:28Z'

.yoi/tickets/00001KW55B32Y/thread.md

@@ -110,3 +110,24 @@ Ticket body / relation / workspace state / accepted plan を確認し、Worker e
 これ以降、worktree creation / coder Worker routing などの implementation side effect に進める。
 
 ---
+
+<!-- event: implementation_report author: yoi-orchestrator at: 2026-06-27T19:09:41Z -->
+
+## Implementation report
+
+Implementation kickoff:
+
+- Worktree created: `/home/hare/Projects/yoi/.worktree/00001KW55B32Y-worker-runtime-execution-backend`
+- Branch: `work/00001KW55B32Y-worker-runtime-execution-backend`
+- Coder Worker spawned: `yoi-coder-00001KW55B32Y-exec-backend`
+
+Scope notes:
+- Coder has read access to the implementation worktree and non-recursive workspace root identity path needed by runtime startup.
+- Coder write scope is limited to `crates/worker-runtime/**`, `crates/workspace-server/**`, root `Cargo.toml`, `Cargo.lock`, and `package.nix` if dependency/package changes are needed.
+- Coder is instructed not to modify Ticket records and not to operate in root/orchestration worktrees.
+
+Queued dependency notes:
+- `00001KW55B33B` remains queued while this execution backend boundary is inprogress.
+- `00001KW55B33H` remains queued behind `00001KW55B33B`.
+
+---