Replace JUST-OS iframe with native API chat client

[LukasWallrich]

Summary

• Replaces the iframe-based JUST-OS chatbot with a native chat client that communicates directly with the public API at bot.just-os.org/chat
• Fixes conversation loss when switching between widget/large/resizable modes (previously each mode created a new iframe session)
• Adds session persistence via sessionStorage so conversation survives same-tab page navigations
• Two display modes: docked right panel (default, 1/3 screen width, full height) and floating centered panel (resizable via drag handle)

What changed

File	Change
layouts/partials/chatbot.html	Rewritten — iframe replaced with native chat UI (messages area, input bar, styled bubbles)
layouts/shortcodes/just_os_chat.html	Rewritten — iframe replaced with full-page chat container
static/js/just-os-chat.js	New — chat client JS: API streaming, state management, UI rendering

Features

• Streaming responses: Shows real-time status updates ("Classifying question", "Finding relevant sources", etc.) while the API processes
• Welcome message on first open
• References: Inline citations displayed as plain text with a collapsible reference list below each bot response (with linked source titles)
• Copy button: Clipboard icon on bot messages (visible on hover)
• New Chat: Resets conversation with fresh chat_id
• Docked ↔ floating toggle: ⤢ button switches between right panel and centered floating window
• Custom resize handle: Bottom-left drag handle in floating mode for resizing
• Responsive: Full-width on mobile; floating mode adapts to smaller screens

Architecture

• Singleton IIFE (JustOSChat) — no global state pollution beyond toggle functions
• API: POST https://bot.just-os.org/chat with { message, chat_id }, streams newline-delimited JSON
• Bot responses rendered as innerHTML (API returns HTML with citation links); user messages as textContent
• sessionStorage persistence keyed by just-os-chat-state
• Widget mode (#just-os-window) on all pages except /just_os_chatbot/; full-page mode (#just-os-fullpage) on the dedicated page

Test plan

• Widget: open/close via icon, send message, receive streaming response
• Docked → floating toggle: verify messages preserved, resize handle appears
• Floating mode: drag bottom-left handle to resize in both directions
• Copy button: hover over bot message, click clipboard icon, verify clipboard
• References: verify collapsible list appears below bot responses with working links
• New Chat: clears conversation, shows welcome message
• Page navigation: navigate away and back in same tab, verify conversation restored
• Dedicated page (/just_os_chatbot/): full-page mode works independently
• Mobile: responsive layout, input visible

Relates to #521

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✅ Spell Check Passed

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[LukasWallrich]

✅ Staging Deployment Status

This PR has been successfully deployed to staging as part of an aggregated deployment.

Deployed at: 2026-03-17 16:58:40 UTC
Staging URL: https://staging.forrt.org

The staging site shows the combined state of all compatible open PRs.

[LukasWallrich]

@richarddushime please review - happy to discuss tomorrow

[richarddushime]

LGTM 🥇