Add optional owo.vg posting backend for 4chan

[4cuck]

Summary

• Adds an optional owo.vg posting backend for 4chan, selectable per-post from the reply box (paw button panel) or configured in site settings.
• Adds Gold Pass login for owo.vg accounts, with saved credentials and auto-login before posting.
• Integrates reply-box extras for owo.vg-specific options (pool selection, captcha mode, gold-only toggles, announcements, feedback, etc.).
• Reuses the existing native 4chan task captcha UI when owo.vg requires a captcha during posting, including solver hint borders (green = selected, orange = suggested).
• Improves HTML error dialogs so rate-limit and help links render correctly instead of showing raw markup.
• Adds email verification hCaptcha support via WebSocket email_hcaptcha prompts with an inline hCaptcha dialog.
• Fixes email verification task captchas to submit solve_email instead of solve, so all four verify stages can complete.
• Shows longer status toasts during email verify (e.g. waiting for / visiting verification link).
• Fixes looping WebSocket status notifications: status toasts are replaced instead of queued, repeated tags refresh in place, and WebSocket events are handled serially.
• Improves WebSocket reliability during long posts: client pings every 20s for server keepalive and a wakelock is held for the duration of posting.

Details

• New service layer handles owo.vg posting, metadata, cookies, and session state.
• 4chan site integration routes submitPost / captcha handling through the selected backend.
• Settings are persisted via new Hive fields (settings.g.dart updated).
• Adds web_socket_channel dependency for posting transport.

Not included

• No signing keys, keystores, or local build config changes.
• No version/build number bumps.

Test plan

• Post to 4chan with default (direct) backend — unchanged behavior
• Switch to owo.vg backend in reply box and post a reply
• Log in with Gold Pass and verify gold-only options appear
• Trigger a captcha and confirm native task UI + hint/selection borders
• Trigger a rate-limit error and confirm line breaks + tappable help link
• Post with Email IPs enabled and complete both hCaptcha stages + both task captchas
• Confirm status toasts appear during email verify (waiting for link, visiting link, context verified)
• Confirm repeated status tags refresh without looping back to older messages
• Confirm WebSocket stays connected during long email verify waits (no random disconnect)
• Verify CI/release build still succeeds without local gradle overrides

[moffatman]

No

[4cuck]

67