Show free trial status and days remaining on account page

[gaidheal1]

Feature Request

Display the user's free trial status on the account page, including how many days remain in their trial.

Motivation

Users who are on a free trial currently have no visibility into their trial status from within the app. Showing this information helps users understand their account status and reduces churn by surfacing the upgrade prompt at the right moment.

Proposed Behaviour

• On the account page, if the user is in a free trial, show a banner or status section indicating:
  • That they are on a free trial
  • How many days are left in the trial (e.g. "7 days remaining")
• Once the trial has ended or the user has subscribed, this section should not be shown (or should update accordingly)

Implementation Notes

• Trial end date is available via the Stripe subscription object (trial_end field) and should already be accessible through the existing payments/subscription backend
• The frontend account page can query the existing subscription status endpoint to retrieve trial info
• Consider showing a link to the upgrade page from this status section

Acceptance Criteria

• Account page shows trial status banner when user is on a free trial
• Banner displays number of days remaining in the trial
• Banner is not shown for non-trial or subscribed users
• Days remaining is accurate and updated on each page load