[Feat] Allow users to link tasks with URLs or notes.

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**Is your feature request related to a problem? Please describe.**
Currently, users cannot associate external resources (like URLs or notes) with their tasks. This limits the ability to keep all relevant information related to a task in one place, requiring users to switch between apps or documents. Enabling task linking to URLs or notes would help users organize their tasks more effectively.

**Describe the solution you'd like**
Add the ability for users to link tasks to URLs (e.g., websites, documents, or other external resources) and attach notes or additional details that could provide more context for the task.
Linking URLs: Users can add a URL to the task that opens in a browser when clicked.
Adding Notes: Users can add short notes or descriptions to tasks, which will be displayed under or alongside the task name.
Both URLs and notes should be visible in the task details view, making it easy for users to access and interact with linked resources.

No files or tests are named. Start by locating the task data model and task details view, then trace task creation and display flows. Done means users can add a clickable URL and a short note, and both appear and remain usable in the task details view.

Written by the indexing model from the issue text.