[BUG] Cloud Routine schedule cannot be edited — neither via API nor the routines UI

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code

### What's Wrong?

A Cloud Routine created via http_api (not through the in-app "New routine" flow) cannot have its cron schedule changed through either supported path:

1. Programmatically: calling update_trigger with a new cron_expression on such a routine is refused with: "this routine was created via 'http_api', not by an agent. Agents can only update routines they created (via create_trigger)."

2. Via the claude.ai/code/routines UI: opening the routine's detail page shows the schedule as plain, non-interactive text ("Runs every Sunday at 11:00 AM") — no click target, pencil icon, or edit control was found after trying: the card's "⋮ → Edit" menu (which just opens the same read-only detail page), clicking directly on the day/time text, clicking the History filter icon, and zooming the page to check for a hidden hover-only icon.

As a workaround, we tried creating a new routine via create_trigger (same prompt, correct schedule) intending to delete the old one afterward. The new routine was created with sources: [], outcomes: [], allowed_tools: [], and no MCP connectors — i.e. no repository access and no basic tool permissions, so it would not have functioned. We deleted it immediately, before any run.

Routines affected (same account):
- trig_018m7xjheBf7Zw9x6F4Ln9sH ("سلطان - توصيات النمو الأسبوعية")
- trig_012eqsHPrBFUf7LRxZhN5b4h ("سلطان - تقرير التحليلات الأسبوعي")
- trig_01N5NoF6FGwZpTDWFZRXnSg4 ("سلطان")

### What Should Happen?

Either the routines UI should expose an editable schedule control for http_api-created routines, or update_trigger/create_trigger should support changing an existing routine's schedule while preserving its repository sources, tool permissions, and MCP connectors.

### Error Messages/Logs

```shell
update_trigger error: "this routine was created via 'http_api', not by an agent. Agents can only update routines they created (via create_trigger)."
```

### Steps to Reproduce

1. Create a Cloud Routine via the http_api (e.g. through this project's Telegram relay flow), not through the in-app "New routine" button.
2. Go to claude.ai/code/routines, open that routine's detail page.
3. Try to change its schedule ("Repeats" section) — the day/time text is not clickable, and no edit control is found via the card's "⋮ → Edit" menu either.
4. As an alternative, from an interactive session call `update_trigger` on that routine's ID with a new `cron_expression` — it is rejected with an ownership error.
5. As another alternative, call `create_trigger` to create a brand-new routine with the same prompt and the desired schedule — the new routine is created but with empty `sources`, `outcomes`, and `allowed_tools`, so it has no repository access or basic tool permissions.

### Claude Model

None

### Is this a regression?

No, this never worked

### Last Working Version

_No response_

### Claude Code Version

N/A — this bug is about claude.ai/code Cloud Routines (a web feature), not the local CLI

### Platform

Anthropic API

### Operating System

macOS

### Terminal/Shell

Terminal.app (macOS)

### Additional Information

_No response_