[Feature Request]: Password manager: auto-try stored passwords for archives and encrypted PDFs

[cn0120]

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• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Describe your suggested feature

HELLO！
I'd like to propose a password manager feature for OpenComic to improve the experience when reading password-protected archives and PDFs.

Problem Currently, every time I open a password-protected archive (ZIP/RAR/7Z) or encrypted PDF, I have to manually enter the password again, even if I've opened it before. This is especially painful when:

• Browsing a folder with many password-protected archives — I have to type the password for each one.

• OpenComic is generating thumbnails — password-protected files get no cover image because there's no way to auto-extract the first page.

Proposed Solution Add a password manager that stores passwords entered by the user (local only, not synced).

1. Auto-try stored passwords on open: When opening a password-protected archive or encrypted PDF, OpenComic should silently try all stored passwords before prompting the user. If a match is found, open directly. Only show the password prompt if no stored password works.
2. Auto-extract cover for password-protected files: During thumbnail/cover generation, automatically try stored passwords to extract the first image/page as the cover, so password-protected files also get proper thumbnails.
3. Password storage UI: A simple management page (e.g. in Settings) to view/delete stored passwords. Passwords should be stored locally and securely (e.g. OS keychain or encrypted local storage).
4. Scope: Applies to ZIP, RAR, 7Z archives and encrypted PDF files.

Why this matters Many comic collections use password protection. This feature would make OpenComic much more convenient for users with large password-protected libraries, and ensure thumbnails work correctly for all files.

Additional Information

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Sample file

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