fix(chat-input): stop template dialogs from sending and fix attachment races

- Template dialogs no longer submit the outer chat form
- Sending is blocked while files or URLs are still extracting
- File and URL extraction no longer drop or resurrect entries
- IME composition Enter no longer sends
- Tool call cards show the error text; keyboard handling on cards fixed
- Template import available when empty, edit dialog resets, saved templates refresh
- Only png/jpeg/gif/webp images accepted, SVG sent as text; PDF objects released
- parse-url request sends the access code

tests/unit/pdf-utils.test.ts

@@ -0,0 +1,16 @@
+import { describe, expect, it } from "vitest"
+import { isTextFile } from "@/lib/pdf-utils"
+
+describe("isTextFile", () => {
+    it("treats SVG files as text so their markup is sent to the model", () => {
+        const svg = new File(["<svg/>"], "diagram.svg", {
+            type: "image/svg+xml",
+        })
+        expect(isTextFile(svg)).toBe(true)
+    })
+
+    it("does not treat raster images as text", () => {
+        const png = new File(["x"], "photo.png", { type: "image/png" })
+        expect(isTextFile(png)).toBe(false)
+    })
+})