Raise ServiceNow changes with the CI, tasks and window right

**Objective:** Create a Normal change "`{summary}`" on `{configuration-item}` planned from `{start-date}` to `{end-date}` (default two hours after the start), with the CI linked and implementation and testing tasks added.

**Step 1: Resolve the CI**

Call `servicenow-get-configuration-item` with name `{configuration-item}`. If nothing matches, retry with name.contains and list the candidates; stop if it is still ambiguous. Keep sys-id, support-group and environment.

**Step 2: Check for clashes**

Call `servicenow-get-ci-affected` with configuration-item `{configuration-item}`. Read each CHG task found with `servicenow-get-change-request`. If any open change overlaps the planned window, show it and ask whether to continue.

**Step 3: Confirm**

Propose: short-description `{summary}`, type Normal, configuration-item, start-date, end-date, assignment-group from the CI's support-group, risk Moderate for Production CIs and Low otherwise, and the two tasks "Implement: `{summary}`" (type Implementation) and "Test: `{summary}`" (type Testing). Ask for an explicit yes, and let the user adjust any value.

**Step 4: Write, in this order**

1. Call `servicenow-add-change-request` once with the confirmed values.
2. Call `servicenow-get-change-request` with short-description.contains `{summary}` and planned-start-date.from the start date to get the new number and sys-id.
3. Call `servicenow-add-ci-affected` once with task set to the change sys-id and configuration-item set to the CI sys-id.
4. Call `servicenow-add-change-task` twice, once per task, with change-request set to the change sys-id and planned dates inside the change window.

**Step 5: Verify and report**

Read back with `servicenow-get-change-task` (change-request = new number) and `servicenow-get-ci-affected` (task = new number). Report the change number, its state, the tasks and the linked CI, and remind the user it still needs approval.

**Rules & Guidelines:**

* Write tools allowed: `servicenow-add-change-request` once, `servicenow-add-ci-affected` once and `servicenow-add-change-task` twice, after one confirmation. Do not call `servicenow-add-approval` or `servicenow-update-change-request`; approval routing is ServiceNow's job.
* If step 4.2 cannot find the new change, stop; never create a second change.

**Validation:**

* If `{end-date}` is before `{start-date}`, stop and ask for corrected dates.