docs: align the docs with the current web UI, CLI and API

[xsmyile]

Reshoots the web UI screenshot with the oxide RustMail palette and fixes stale statements: palette descriptions, focus outline, default database path, binary and image sizes, WebSocket and webhook payloads, assertion defaults, release TLS, assert flags and the architecture diagram.

[pullfrog]

ℹ️ One documentation correction inline; no runtime regressions found.

Reviewed changes Reviewed the documentation refresh and replacement screenshot against the current implementation.

• Web UI Updated palette descriptions, keyboard focus behavior, and the screenshot.
• CLI and setup Corrected assertion options, the default database location, version examples, and size estimates.
• API and delivery Updated assertion defaults, webhook/WebSocket payloads, connection lifecycle, release TLS behavior, and the SMTP delivery diagram.

  ^{｜ Fix all ➔ ｜ Fix 👍s ➔ ｜ View workflow run ｜ Using gpt-6.1-sol ｜ 𝕏}

[pullfrog]

✅ No new issues found.

Reviewed changes Reviewed the documentation correction in 782bfc0 against the webhook startup validator.

• Clarified webhook restrictions Scoped startup rejection to localhost and private/reserved IP literals, explicitly noting that hostnames are not resolved and can point to those addresses.

No tests were run because the delta changes documentation only.

  ^{｜ View workflow run ｜ Using gpt-6.1-sol ｜ 𝕏}