feat: Support for creating custom categories and renaming queues

[sudosz]

Preflight checklist

• I searched existing issues and this has not been proposed already.
• I checked the README and this is not already supported.

Component

Desktop GUI (Hydra Download Manager)

Problem

Currently, the categories in Hydra are fixed and cannot be added to or customized. Additionally, users cannot create or rename download queues. This makes it difficult to organize large numbers of downloads.

For example, if I want to download a game that has 40 parts, or organize my programming-related downloads or TV series, they all get mixed up in the default categories. It would be incredibly helpful to group specific files together to easily start or schedule them (e.g., scheduling a whole custom category to download at 2 AM).

Proposed solution

Allow users to create, rename, and manage custom categories and queues in the GUI. Users should be able to assign downloads to these custom categories and schedule or start the entire category/queue as a batch.

Alternatives considered

Relying on the default categories and manually selecting multiple files to start or schedule them, which is tedious and clutters the download list.

Platforms this should cover

• Linux
• macOS
• Windows
• Android / iOS (via libhydra)

Additional context

No response

Compatibility

• This changes existing behavior (flags, defaults, output format, or the C ABI).

Contribution

• I'm willing to open a pull request implementing this.

[uDEV2019]

Until this feature will be shipped, is is easily possible to work around this:

1. go to %appdata%\hydra and open config.toml with Editor
2. search for [[categories]] and copy it like this:

3. save config.toml and launch Hydra