Add multi-account support

[nianshou555qiansui]

Summary

Adds multi-account support so a single fork can claim Epic freebies for several accounts in one run, while staying fully backward compatible with the existing single-account setup.

This is a re-submission of #15 addressing the two review points:

1. Fall back to EPIC_EMAIL / EPIC_PASSWORD when EPIC_ACCOUNTS is set but contains no valid entries, so a malformed secret can't break an already-working single-account repo.
2. Make the job timeout configurable via a repository variable instead of a hard-coded 30 minutes.

Changes

• New app/accounts.py: parse_accounts() reads credentials from EPIC_ACCOUNTS (multiline email:password, one per line) with priority, and falls back to EPIC_EMAIL / EPIC_PASSWORD if EPIC_ACCOUNTS is unset or has no valid lines. Passwords may contain colons (split on first : only). Emails are masked before logging.
• app/deploy.py: new _run_accounts() iterates every configured account sequentially. A failure in one account is logged and the run continues to the next; the job exits non-zero only if at least one account failed, with a summary of successes/failures.
• app/settings.py: adds optional EPIC_ACCOUNTS secret; EPIC_EMAIL / EPIC_PASSWORD now default to empty so an accounts-only setup starts cleanly.
• .github/workflows/epic-gamer.yml: timeout-minutes now reads the JOB_TIMEOUT_MINUTES repository variable (default 60), and passes EPIC_ACCOUNTS through to the run.
• .env.example / README.md / README.en.md: document multi-account config and the timeout variable.

Behavior notes

• Multi-account runs are sequential, so the timeout scales with account count — hence the configurable JOB_TIMEOUT_MINUTES.
• If any account fails, the whole job is marked failed, while still attempting every configured account first. This keeps failures visible while avoiding one broken account blocking the rest.
• EPIC_ACCOUNTS is intended for GitHub Actions secrets. Local .env parsers may not support multiline values, so single-account local runs should keep using EPIC_EMAIL / EPIC_PASSWORD (noted in .env.example).

Compatibility

Existing setups that only use EPIC_EMAIL / EPIC_PASSWORD need no changes and behave exactly as before.

[Ronchy2000]

Thanks for the update. The two compatibility concerns raised on the previous PR — the workflow timeout and fallback behavior for an invalid EPIC_ACCOUNTS value — have now been addressed.

I would like to keep this PR open and deploy the current revision to a dedicated preview branch for a short soak-testing period before merging it into master. I will run several real multi-account workflow executions and review the logs and artifacts to make sure the behavior remains stable across multiple runs.

[nianshou555qiansui]

Thanks for the review! I've updated the branch with the latest master (the hcaptcha fixes and #20) and resolved the merge conflicts, so it's clean to merge again — a preview branch cut from the current head would include the up-to-date captcha stack for the soak runs. Let me know if anything comes up during testing.