test(web): cover empty-draft queue flush with a keyless replay scenario

Also pin the queue-item-not-found convergence arm through the hub and
document the repeated-trigger contract on steerQueue.

apps/web/tests/snapshots/steer-all/mid-steer.expected.md

@@ -0,0 +1,36 @@
+- banner:
+  - navigation "Session hierarchy":
+    - button "Use the ask_user_question tool to" [disabled]
+  - tablist:
+    - tab "Chat" [selected]
+    - tab "Trajectory"
+- text: Use the ask_user_question tool to ask me exactly one question with id "checkpoint", question "Ready to continue?", header "Checkpoint", and options labeled "Yes" and "No". After I answer, reply with one short sentence acknowledging my answer and stop. {{clock}}
+- button "Copy":
+  - img
+- button "Branch into a new conversation" [disabled]:
+  - img
+- text: Available only on the last message of a completed turn
+- button "Context injection @deepseek-ai/dsh-system-prompt":
+  - img
+  - img
+  - text: Context injection @deepseek-ai/dsh-system-prompt
+- text: Running
+- button "Think":
+  - img
+  - img
+  - text: Think
+- status: Deep diving...
+- text: "Interjection Interjection: include the word BANANA in your final reply."
+- button "Copy":
+  - img
+- text: "Interjection Interjection: include the word ORANGE in your final reply."
+- button "Copy":
+  - img
+- textbox "Message the agent"
+- button "Commands":
+  - img
+- 'button "Access mode, current: Workspace Write"': Workspace Write
+- button "Select model, current DeepSeek-V4-Flash":
+  - text: DeepSeek-V4-Flash
+  - img
+- button "Stop generating"

apps/web/tests/snapshots/steer-all/replay.override.json

@@ -0,0 +1,47 @@
+[
+  {
+    "kind": "chunks",
+    "chunks": [
+      { "type": "block-start", "index": 0, "blockType": "reasoning" },
+      { "type": "reasoning-delta", "index": 0, "text": "The user wants me to ask them a checkpoint question first, then continue with whatever they interject. Let me do exactly that." },
+      { "type": "block-start", "index": 1, "blockType": "tool-call" },
+      {
+        "type": "tool-call-delta",
+        "index": 1,
+        "id": "call_00_steer_all",
+        "name": "ask_user_question",
+        "argumentsDelta": "{\"questions\": [{\"id\": \"checkpoint\", \"question\": \"Ready to continue?\", \"header\": \"Checkpoint\", \"options\": [{\"label\": \"Yes\"}, {\"label\": \"No\"}]}]}"
+      },
+      {
+        "type": "block-end",
+        "index": 0,
+        "block": {
+          "type": "reasoning",
+          "text": "The user wants me to ask them a checkpoint question first, then continue with whatever they interject. Let me do exactly that."
+        }
+      },
+      {
+        "type": "block-end",
+        "index": 1,
+        "block": {
+          "type": "tool-call",
+          "id": "call_00_steer_all",
+          "name": "ask_user_question",
+          "arguments": "{\"questions\": [{\"id\": \"checkpoint\", \"question\": \"Ready to continue?\", \"header\": \"Checkpoint\", \"options\": [{\"label\": \"Yes\"}, {\"label\": \"No\"}]}]}"
+        }
+      },
+      { "type": "usage", "usage": { "inputTokens": 10, "outputTokens": 10, "cacheReadTokens": 0, "reasoningTokens": 0 } },
+      { "type": "finish", "reason": { "kind": "tool-calls" } }
+    ]
+  },
+  {
+    "kind": "chunks",
+    "chunks": [
+      { "type": "block-start", "index": 0, "blockType": "text" },
+      { "type": "text-delta", "index": 0, "text": "Got it: BANANA and ORANGE." },
+      { "type": "block-end", "index": 0, "block": { "type": "text", "text": "Got it: BANANA and ORANGE." } },
+      { "type": "usage", "usage": { "inputTokens": 10, "outputTokens": 10, "cacheReadTokens": 0, "reasoningTokens": 0 } },
+      { "type": "finish", "reason": { "kind": "stop" } }
+    ]
+  }
+]

apps/web/tests/snapshots/steer-all/settled.expected.md

@@ -0,0 +1,51 @@
+- banner:
+  - navigation "Session hierarchy":
+    - button "Use the ask_user_question tool to" [disabled]
+  - tablist:
+    - tab "Chat" [selected]
+    - tab "Trajectory"
+- text: Use the ask_user_question tool to ask me exactly one question with id "checkpoint", question "Ready to continue?", header "Checkpoint", and options labeled "Yes" and "No". After I answer, reply with one short sentence acknowledging my answer and stop. {{clock}}
+- button "Copy":
+  - img
+- button "Branch into a new conversation" [disabled]:
+  - img
+- text: Available only on the last message of a completed turn
+- button "Context injection @deepseek-ai/dsh-system-prompt":
+  - img
+  - img
+  - text: Context injection @deepseek-ai/dsh-system-prompt
+- button "Think The user wants me to ask them a checkpoint question first, then continue with whatever they interject. Let me do exactly that.":
+  - img
+  - img
+  - text: Think The user wants me to ask them a checkpoint question first, then continue with whatever they interject. Let me do exactly that.
+- button "Ask question 1/1 answered":
+  - img
+  - img
+  - text: Ask question 1/1 answered
+- text: "Interjection Interjection: include the word BANANA in your final reply. {{clock}}"
+- button "Copy":
+  - img
+- button "Branch into a new conversation" [disabled]:
+  - img
+- text: "Available only on the last message of a completed turn Interjection Interjection: include the word ORANGE in your final reply. {{clock}}"
+- button "Copy":
+  - img
+- button "Branch into a new conversation" [disabled]:
+  - img
+- text: Available only on the last message of a completed turn
+- paragraph: "Got it: BANANA and ORANGE."
+- button "Copy":
+  - img
+- button "Branch into a new conversation":
+  - img
+- text: {{clock}} Ran for {{duration}} TTFT {{duration}} {{throughput}} tok/s
+- textbox "Message the agent"
+- button "Commands":
+  - img
+- 'button "Access mode, current: Workspace Write"': Workspace Write
+- button "Select model, current DeepSeek-V4-Flash":
+  - text: DeepSeek-V4-Flash
+  - img
+- button "0% of context used"
+- button "Send message" [disabled]
+- text: 1 turns · 2 steps LLM {{duration}} · Tool call {{duration}} TTFT avg {{duration}} · {{throughput}} tok/s Cache hit 0% Input 20 tok · Output 20 tok