Step 3: move the agent-merge note and image into the test-watch step

The 'Agent merge usually happens automatically' note and the Agent merge
dropdown image belong with watching the agent open the pull request, not
with reviewing the diff. Move them from the review step into step 4 so the
flow reads: agent opens the PR via agent merge, then you review the diff.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: a9ddd07b-77bf-43e0-a5d9-c6426a067e0e

Author: arilivigni

.github/steps/3-step.md

@@ -97,13 +97,13 @@ A few things to know about the build:
 
    <img width="360" alt="The build prompt in the session with the Build the bookmarks app issue #2 referenced as a chip" src="../images/step3-issue-prompt.png" />
 1. **Watch the agent test the implementation.** Building the feature includes verifying it — Copilot runs the **unit tests** you asked for and the **production build**, all headless: no browser opens and the Playwright MCP server stays idle. The tests cover URL normalisation, corrupted-storage recovery, and the exact `" :: "` formatting, while the build proves `localStorage` stays behind the `client:load` boundary. You'll preview the app live and drive it with Playwright in **Step 4** — here the tests and build are enough to trust the diff before you merge.
-1. **Review the diff before you merge.** Agent merge opens the pull request that links issue **#2** for you — review the changes in the session's **Changes** tab (or a browser canvas on the PR). You'll merge it in **Activity 2** once you're satisfied.
-
-   <img width="440" alt="Session review of the base62 nextSlug helper (mona- prefixed slugs), persistence and event-wiring notes, with Changes +107 -21 and PR #4 buttons at the bottom" src="../images/ghcp-app-step3.png" />
 
    **Agent merge usually happens automatically.** The agent opens the pull request for you via **agent merge**, so you may never open the action dropdown — the view below is optional. If no pull request appears (or you'd rather trigger it yourself), open the session's action dropdown and select **Agent merge**:
 
    <img width="380" alt="Session action dropdown with Agent merge selected — 'Automate your pull request lifecycle' — above Create PR and Create draft PR" src="../images/ghcp-app-agent-merge.png" />
+1. **Review the diff before you merge.** Agent merge opens the pull request that links issue **#2** for you — review the changes in the session's **Changes** tab (or a browser canvas on the PR). You'll merge it in **Activity 2** once you're satisfied.
+
+   <img width="440" alt="Session review of the base62 nextSlug helper (mona- prefixed slugs), persistence and event-wiring notes, with Changes +107 -21 and PR #4 buttons at the bottom" src="../images/ghcp-app-step3.png" />
 
    <details>
    <summary>Walk the diff before you merge 👀</summary><br/>