Add debrid provider priority

[ALenfant]

📌 Description

Specify a priority value for configured Debrid services.

They are then tried in order of increasing priority (1, 2, ...)

Fixes #285, although I decided to let the user specify the priority order by a new field, as re-ordering configured debrid services was a bit trickier

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Target Branch Check (IMPORTANT)

• I confirm this PR is targeting the correct branch

Expected target:

• beta (for features)

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Changes Made

• Backend Configuration: Added priority field to the Debrid struct in internal/config/debrid.go.
• Logic Implementation: Updated FilterDebrid in pkg/manager/debrid.go to sort clients by priority (lower values first), using the provider name as a secondary sort key for consistent ordering.
• Web UI: Added a Priority input field to the Debrid configuration section in pkg/server/assets/js/config.js, enabling users to manage priorities via the dashboard.
• Documentation: Updated the configuration guide in docs/src/content/docs/guides/configuration.md to document the new priority field.

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Testing

• Tested locally

Steps:

1. Added multiple debrid providers with a specific priority (ServiceA then ServiceB)
2. Attempted to download a test torrent known to fail on ServiceA but work on ServiceB
3. Decypharr first tried ServiceA, then fell back on ServiceB as expected
4. Reversed the priority order, ServiceB was used first as expected

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Risks / Notes

• Default priority is 0. Providers with equal priority are sorted alphabetically by their configured name.
• Non-breaking change: existing configurations will default to 0 and continue to function as before.

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Screenshots (if applicable)

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Checklist

• Code builds successfully
• No console/log errors
• Reviewed my own code
• Target branch is correct