allozaur/feat/chat slash commands (#26716)

* base : slash-command/misc foundation - model icon and focus-selector constants

* feat : slash-command picker and command parsing helpers

* refactor : wire command and @-mention pickers into the chat form

* ui : improve model selector keyboard navigation and load/dismiss

* feat: Unify markdown/raw-text rendering under one setting with migration

* fix: Misc fixes - tool-call subtitle, assistant wrap, progress guards

* feat: Clamp and style numeric settings inputs from registry bounds

tools/ui/src/lib/components/app/chat/ChatMessages/ChatMessageAgenticContent.svelte

@@ -41,7 +41,6 @@
 
 	let expandedStates: Record<number, boolean> = $state({});
 
-	const renderThinkingAsMarkdown = $derived(config().renderThinkingAsMarkdown as boolean);
 	const showThoughtInProgress = $derived(Boolean(config().showThoughtInProgress));
 	const alwaysShowToolCallContent = $derived(Boolean(config().alwaysShowToolCallContent));
 	const showMessageStats = $derived(Boolean(config().showMessageStats));
@@ -186,7 +185,6 @@
 			{section}
 			open={isExpanded(index, section)}
 			{isStreaming}
-			{renderThinkingAsMarkdown}
 			{hasReasoningError}
 			attachments={message?.extra}
 			onToggle={() => toggleExpanded(index, section)}