fix(app): make composer input IME-safe and paste-aware (#3343)

* fix(app): preserve native composer input semantics

Native text was round-tripped through application state on every keystroke, which could overwrite an input method's in-flight edits. Keep native text ownership inside the input and reserve application-driven replacement for explicit draft mutations.\n\nRoute native clipboard images through the existing persisted attachment pipeline so keyboard and system paste actions behave like other image sources.

* fix(nix): refresh dependency hash

The native composer dependency changes the fixed npm dependency closure used by desktop builds.

* fix(app): keep composer locked across image pastes

Count concurrent native image persistence operations so submit remains disabled until every pasted image is attached.

* fix(app): replace composer text through the DOM on web

Web TextInput refs are DOM elements, so application-driven draft replacement must update their value and selection without native setNativeProps.

* fix(app): preserve web IME composition

Carry the Chinese IME fix from #2990 into the web composer input boundary.

Co-authored-by: Jimmy Lee <jimersylee+github@gmail.com>

---------

Co-authored-by: Jimmy Lee <jimersylee+github@gmail.com>

package-lock.json

@@ -7762,6 +7762,16 @@
       "integrity": "sha512-l0h88YhZFyKdXIFNfSWpyjStDjGHwZ/U7iobcK1cQQD8sejsONdQtTVU+1wVN1PBw40PiiHB1vA5S7VTfQiP9g==",
       "license": "MIT"
     },
+    "node_modules/@mattermost/react-native-paste-input": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/@mattermost/react-native-paste-input/-/react-native-paste-input-2.0.1.tgz",
+      "integrity": "sha512-Q9zjXvjwxVQ1M8ylxr9Y+wUpG7xb1wW4u+I34oPvF3etTyBrGtVyA4Bt7Xphgc29eW6wQFUxTIbzZc3E6W2MQg==",
+      "license": "MIT",
+      "peerDependencies": {
+        "react": "*",
+        "react-native": ">=0.76.0"
+      }
+    },
     "node_modules/@mermaid-js/parser": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/@mermaid-js/parser/-/parser-1.2.0.tgz",
@@ -36108,6 +36118,7 @@
         "@getpaseo/protocol": "*",
         "@gorhom/bottom-sheet": "^5.2.14",
         "@gorhom/portal": "^1.0.14",
+        "@mattermost/react-native-paste-input": "2.0.1",
         "@react-native-async-storage/async-storage": "2.2.0",
         "@react-native-masked-view/masked-view": "^0.3.2",
         "@react-native/normalize-colors": "^0.81.5",