Media transfers (#440)

* tor voice wip

* worky BLE a bit

* can send sound

* remove tor

* ui cleanup

* recording time

* progress bar color

* nicknames for audio

* onboarding permissions no microphone

* may work

* fix destionation

* extend

* refactor voice input component

* fix keyboard collapse issue

* send images

* wip image open

* image sending works

* wip waveforms

* better

* better animation

* fix cursor for sending audio

* image sending animation

* image sending animation

* full screen image viewer

* gossip sync for fragments too

* reduce delays

* fix keyboard focus

* use v2 for file transfers

* do not sync fragments

* scrollable image viewer

* ui

* ui adjustments

* nicer animation

* seek through audio

* add spec

* add more details to documentation

* File sharing E2E:
- Add TLV BitchatFilePacket, FileSharingManager
- Implement sendFileNote in ChatViewModel
- File receive path: save to files/incoming and render [file] messages with FileMessageItem or FileSendingAnimation during transfer
- SAF FilePickerButton and dispatcher wiring; image/file choice to follow in MediaPickerOptions
- Add FileViewerDialog with system open/save, FileProvider and file_paths
- Hook transfer progress to file sending UI
- Manifest: READ_MEDIA_* and FileProvider
- Fix MessageHandler saving and prefix for non-image payloads
- Add helper utils (FileUtils)

* kinda wip

* fix buttons

* files half working

* wip file transfer

* file packet has 2-byte TLV and chunks. it wokrs but it sucks

* clean

* remove gossip sync for fragments

* fix audio and image rendering

* adjust FILE_SIZE TLV size too

* cleanup

* haptic

* private messages media

* read receipts for media

* use enum for message type not string

* delivery ack checks dont push content

* check

* animation fix

* refactor

* ui adjustments

* comments

* refactor

* fix crash on send and receive of the same file

* refactor notifications

* tests

app/src/main/java/com/bitchat/android/ui/events/FileShareDispatcher.kt

@@ -0,0 +1,17 @@
+package com.bitchat.android.ui.events
+
+/**
+ * Lightweight dispatcher so lower-level UI (MessageInput) can trigger
+ * file sending without holding a direct reference to ChatViewModel.
+ */
+object FileShareDispatcher {
+    @Volatile private var handler: ((String?, String?, String) -> Unit)? = null
+
+    fun setHandler(h: ((String?, String?, String) -> Unit)?) {
+        handler = h
+    }
+
+    fun dispatch(peerIdOrNull: String?, channelOrNull: String?, path: String) {
+        handler?.invoke(peerIdOrNull, channelOrNull, path)
+    }
+}