## Summary
Subagent (child) chats were previously given access to workspace
provisioning tools (`list_templates`, `read_template`,
`create_workspace`), which could lead to uncontrolled resource
consumption. This PR moves those tools behind the same
`!chat.ParentChatID.Valid` gate that already protects the subagent tools
(`spawn_agent`, `wait_agent`, etc.).
## Changes
- **`coderd/chatd/chatd.go`**: Moved `list_templates`, `read_template`,
and `create_workspace` tool registration into the root-chat-only block
alongside subagent tools.
- **`coderd/chatd/chatd_test.go`**: Added
`TestSubagentChatExcludesWorkspaceProvisioningTools` — an E2E test that
spawns a subagent via a root chat and verifies the subagent's LLM call
does not include workspace provisioning or subagent tools.
- **`coderd/chatd/chattest/openai.go`**: Added `Tools` field to
`OpenAIRequest` and supporting `OpenAITool`/`OpenAIToolFunction` types
so tests can inspect which tools are sent to the model.
Fixes https://github.com/coder/internal/issues/1371
## Problem
`TestCloseDuringShutdownContextCanceledShouldRetryOnNewReplica` flakes
intermittently in CI. The observed failure is that the chat never
reaches `pending` status after `serverA.Close()`.
## Root cause
Race between context cancellation and the mock OpenAI server's stream
completion marker.
When `Close()` cancels the server context, the in-flight HTTP streaming
request is canceled. The mock server's handler detects this via
`req.Context().Done()` and closes its chunks channel. The mock's
`writeChatCompletionsStreaming` then writes `data: [DONE]` — the SSE
completion marker. On a loopback connection, this marker can reach the
client **before** the client's HTTP transport honors the context
cancellation.
When this happens:
1. The client sees a successful stream completion (not an error)
2. `chatloop.Run` returns `nil`
3. `processChat` falls through without error → status stays `waiting`
(the default)
4. The test expects `pending` → **flake**
## Fix
Skip writing the `[DONE]` marker when the request context is already
canceled, in both `writeChatCompletionsStreaming` and
`writeResponsesAPIStreaming`.
Kyle Carberry