Replace the composer textarea with a Tiptap markdown editor

The composer now writes markdown with bold, italic, strike, code,
links, quotes and lists, from shortcuts, markdown typing or a bubble
over the selection. @ mentions a bot and # a workspace, shown as chips
and saved as [bot:ID] / [workspace:ID]. Text selected in a message can
be quoted into the composer. User messages render as markdown, and
replies tell the bot who and what the user mentioned.

Adds an ESM stand-in for use-sync-external-store, since bunext keeps
React external in page bundles and the CommonJS original requires it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/use-sync-external-store-esm/index.js

@@ -0,0 +1,4 @@
+/**
+ * React 18+ has `useSyncExternalStore`; the shim only re-exports it.
+ */
+export { useSyncExternalStore } from "react";

packages/use-sync-external-store-esm/package.json

@@ -0,0 +1,21 @@
+{
+    "name": "use-sync-external-store",
+    "version": "1.7.0-esm",
+    "description": "ESM stand-in for use-sync-external-store on React 19, which has useSyncExternalStore built in. The page bundler keeps react external, so the upstream CommonJS require(\"react\") can't load in the browser.",
+    "license": "MIT",
+    "type": "module",
+    "sideEffects": false,
+    "exports": {
+        ".": "./index.js",
+        "./with-selector": "./with-selector.js",
+        "./with-selector.js": "./with-selector.js",
+        "./shim": "./index.js",
+        "./shim/index.js": "./index.js",
+        "./shim/with-selector": "./with-selector.js",
+        "./shim/with-selector.js": "./with-selector.js",
+        "./package.json": "./package.json"
+    },
+    "peerDependencies": {
+        "react": ">=18"
+    }
+}

packages/use-sync-external-store-esm/shim/index.js

@@ -0,0 +1 @@
+export { useSyncExternalStore } from "../index.js";

packages/use-sync-external-store-esm/shim/with-selector.js

@@ -0,0 +1 @@
+export { useSyncExternalStoreWithSelector } from "../with-selector.js";

packages/use-sync-external-store-esm/with-selector.js

@@ -0,0 +1,69 @@
+/**
+ * `useSyncExternalStoreWithSelector` from React's use-sync-external-store
+ * (MIT, Meta Platforms, Inc. and affiliates), as an ES module: it reads a
+ * store through a selector and only re-renders when the selection
+ * changes (`isEqual`).
+ */
+import { useDebugValue, useEffect, useMemo, useRef, useSyncExternalStore } from "react";
+
+export function useSyncExternalStoreWithSelector(subscribe, getSnapshot, getServerSnapshot, selector, isEqual) {
+    const instRef = useRef(null);
+
+    if (instRef.current === null) instRef.current = { hasValue: false, value: null };
+
+    const inst = instRef.current;
+
+    const [getSelection, getServerSelection] = useMemo(() => {
+        let hasMemo = false;
+        let memoizedSnapshot;
+        let memoizedSelection;
+
+        const memoizedSelector = (nextSnapshot) => {
+            if (!hasMemo) {
+                hasMemo = true;
+                memoizedSnapshot = nextSnapshot;
+
+                const nextSelection = selector(nextSnapshot);
+
+                if (isEqual !== undefined && inst.hasValue && isEqual(inst.value, nextSelection)) {
+                    memoizedSelection = inst.value;
+                    return memoizedSelection;
+                }
+
+                memoizedSelection = nextSelection;
+                return nextSelection;
+            }
+
+            const currentSelection = memoizedSelection;
+
+            if (Object.is(memoizedSnapshot, nextSnapshot)) return currentSelection;
+
+            const nextSelection = selector(nextSnapshot);
+
+            if (isEqual !== undefined && isEqual(currentSelection, nextSelection)) {
+                memoizedSnapshot = nextSnapshot;
+                return currentSelection;
+            }
+
+            memoizedSnapshot = nextSnapshot;
+            memoizedSelection = nextSelection;
+            return nextSelection;
+        };
+
+        return [
+            () => memoizedSelector(getSnapshot()),
+            getServerSnapshot === undefined ? undefined : () => memoizedSelector(getServerSnapshot()),
+        ];
+    }, [getSnapshot, getServerSnapshot, selector, isEqual]);
+
+    const value = useSyncExternalStore(subscribe, getSelection, getServerSelection);
+
+    useEffect(() => {
+        inst.hasValue = true;
+        inst.value = value;
+    }, [value]);
+
+    useDebugValue(value);
+
+    return value;
+}