ticket: start websocket observation proxy

.yoi/tickets/00001KVZKSTJT/item.md

@@ -2,7 +2,7 @@
 title: 'Runtime/Backend WebSocket observation proxyを実装する'
 state: 'inprogress'
 created_at: '2026-06-25T14:44:02Z'
-updated_at: '2026-06-26T04:22:27Z'
+updated_at: '2026-06-26T04:23:22Z'
 assignee: null
 queued_by: 'workspace-panel'
 queued_at: '2026-06-25T20:34:20Z'

.yoi/tickets/00001KVZKSTJT/thread.md

@@ -254,3 +254,23 @@ Dependency `00001KVZKSTE2` REST command server は done。Ticket body/thread、r
 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: 2026-06-26T04:23:22Z -->
+
+## Implementation report
+
+Implementation kickoff:
+
+- Worktree created: `/home/hare/Projects/yoi/.worktree/00001KVZKSTJT-websocket-observation-proxy`
+- Branch: `work/00001KVZKSTJT-websocket-observation-proxy`
+- Coder Worker spawned: `yoi-coder-00001KVZKSTJT-ws-proxy`
+
+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`.
+- Coder is instructed not to modify Ticket records and not to operate in root/orchestration worktrees.
+
+Next action:
+- Wait for Coder implementation report, then route to reviewer.
+
+---