webui: add OAI-Compat Harmony tool-call streaming visualization and persistence in chat UI (#16618)

* webui: add OAI-Compat Harmony tool-call live streaming visualization and persistence in chat UI

- Purely visual and diagnostic change, no effect on model context, prompt
  construction, or inference behavior

- Captured assistant tool call payloads during streaming and non-streaming
  completions, and persisted them in chat state and storage for downstream use

- Exposed parsed tool call labels beneath the assistant's model info line
  with graceful fallback when parsing fails

- Added tool call badges beneath assistant responses that expose JSON tooltips
  and copy their payloads when clicked, matching the existing model badge styling

- Added a user-facing setting to toggle tool call visibility to the Developer
  settings section directly under the model selector option

* webui: remove scroll listener causing unnecessary layout updates (model selector)

* Update tools/server/webui/src/lib/components/app/chat/ChatMessages/ChatMessageAssistant.svelte

Co-authored-by: Aleksander Grygier <aleksander.grygier@gmail.com>

* Update tools/server/webui/src/lib/components/app/chat/ChatMessages/ChatMessageAssistant.svelte

Co-authored-by: Aleksander Grygier <aleksander.grygier@gmail.com>

* chore: npm run format & update webui build output

* chore: update webui build output

---------

Co-authored-by: Aleksander Grygier <aleksander.grygier@gmail.com>

tools/server/webui/src/lib/constants/settings-config.ts

@@ -6,6 +6,7 @@ export const SETTING_CONFIG_DEFAULT: Record<string, string | number | boolean> =
 	theme: 'system',
 	showTokensPerSecond: false,
 	showThoughtInProgress: false,
+	showToolCalls: false,
 	disableReasoningFormat: false,
 	keepStatsVisible: false,
 	showMessageStats: true,
@@ -80,6 +81,8 @@ export const SETTING_CONFIG_INFO: Record<string, string> = {
 	custom: 'Custom JSON parameters to send to the API. Must be valid JSON format.',
 	showTokensPerSecond: 'Display generation speed in tokens per second during streaming.',
 	showThoughtInProgress: 'Expand thought process by default when generating messages.',
+	showToolCalls:
+		'Display tool call labels and payloads from Harmony-compatible delta.tool_calls data below assistant messages.',
 	disableReasoningFormat:
 		'Show raw LLM output without backend parsing and frontend Markdown rendering to inspect streaming across different models.',
 	keepStatsVisible: 'Keep processing statistics visible after generation finishes.',