fix(odin): clear composer on send + readable selection in user bubble

- the sent message now leaves the input the moment the optimistic bubble
  appears (restored along with attachments if the request fails)
- text selected in the primary-filled user bubble inverts to
  white-on-primary instead of vanishing into the global ::selection style

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/admin/components/odin/OdinChat.tsx

@@ -216,6 +216,8 @@ export default function OdinChat() {
     // tools over system data); attachments keep the invoice-extract path.
     setBusy(true);
     const prevTurns = turns;
+    const prevInput = input;
+    const prevAttachments = attachments;
 
     const userContent = [
       text,
@@ -228,6 +230,10 @@ export default function OdinChat() {
       { role: "user", content: userContent },
     ];
     setTurns(optimistic);
+    // Clear the composer immediately — the message now lives in the thread
+    // as the optimistic bubble; a failure restores both below.
+    setInput("");
+    setAttachments([]);
 
     try {
       if (files.length > 0) {
@@ -268,8 +274,6 @@ export default function OdinChat() {
         setReview((prev) => [...prev, ...reviews]);
         const note = summaryNote(reviews);
         setTurns((t) => [...t, { role: "assistant", content: note }]);
-        setInput("");
-        setAttachments([]);
         // Create the conversation now (first successful message) and persist.
         const convId = await ensureActive();
         if (convId != null)
@@ -293,7 +297,6 @@ export default function OdinChat() {
           ? body.data.tool_trace
           : undefined;
         setTurns((t) => [...t, { role: "assistant", content: reply, tools }]);
-        setInput("");
         // Create the conversation now (first successful message) and persist.
         const convId = await ensureActive();
         if (convId != null)
@@ -305,6 +308,9 @@ export default function OdinChat() {
       }
     } catch (e) {
       setTurns(prevTurns);
+      // Give the user their message back to retry/edit.
+      setInput(prevInput);
+      setAttachments(prevAttachments);
       const fallback = files.length > 0 ? "Chyba čtení faktur" : "Chyba AI";
       alert.error(e instanceof Error ? e.message : fallback);
     } finally {