feat: attach desktop file paths as editable learner chips

components/home.tsx

@@ -13,6 +13,7 @@ import { useFieldCycle } from "@/components/field-cycle";
 import { SidebarToggle } from "@/components/sidebar";
 import { StatsBar } from "@/components/stats-bar";
 import { OPENING_PROMPT_FAILURE } from "@/components/opening-prompt";
+import { PathInput } from "@/components/path-input";
 import { SessionStarter } from "@/components/start-session";
 import type { TurnUsage } from "@/src/core";
 
@@ -64,7 +65,7 @@ export function Home({
 	/* Run end focuses the topic input (owner, 2026-10-01): the hands are on
 	 * the keyboard from the stop. Falling edge only; this surface's only
 	 * dictation target IS this textarea, so no case-split is needed. */
-	const topicInputRef = useRef<HTMLTextAreaElement>(null);
+	const topicInputRef = useRef<HTMLDivElement>(null);
 	// Tab navigates INTO the topic composer (owner, keyboard round
 	// 2026-10-06): the only text field on this surface — and home's
 	// composer is its OWN textarea, not the shared Composer component,
@@ -248,13 +249,14 @@ export function Home({
 						void start();
 					}}
 				>
-					<textarea
+					<PathInput
 						ref={topicInputRef}
 						value={topic}
-						onChange={(e) => {
-							topicRef.current = e.target.value;
-							setTopic(e.target.value);
+						onValueChange={(value) => {
+							topicRef.current = value;
+							setTopic(value);
 						}}
+						defaultDropTarget
 						onKeyDown={(e) => {
 							// Esc ends dictation (the dictate decisions: click-again or
 							// Esc) — stopPropagation claims it (keyboard wave A) so
@@ -272,7 +274,6 @@ export function Home({
 						}}
 						placeholder={mode === "practice" ? "What do you want to practice?" : "What do you want to learn?"}
 						autoFocus
-						rows={1}
 						className="field-sizing-content lh-input max-h-48 min-h-10 flex-1 resize-none bg-transparent px-2.5 py-2 outline-none placeholder:text-muted-foreground"
 					/>
 					{/* No tooltip on the start square — the ↵ glyph is the