update readmes

RandomFileSenderBot/README.md

@@ -1,9 +1,76 @@
 # RandomFileSenderBot
 
-This bot will send random file from input folder OR from bot working folder
+This Kotlin Multiplatform example sends randomly selected local files in response to a Telegram command. It uses long
+polling and can run on the JVM or as a Kotlin/Native executable.
 
-## Launch
+## Behavior
+
+The bot registers one command:
+
+- `/send_file` requests one file;
+- `/send_file N` requests `N` files when `N` is a positive integer; and
+- a missing or non-numeric count defaults to one. Zero and negative counts select nothing and receive
+  `Nothing selected :(`.
+
+For each requested file, the picker starts at the configured root. A file root is selected directly; a directory root
+is searched by choosing one random child at each level until a file is reached. This is not a uniform choice among all
+files in an uneven directory tree, and the same file may be selected more than once. Zero-byte files and unsuccessful
+selections are retried. Consequently, a positive request can keep retrying indefinitely when no non-empty file is
+reachable.
+
+One file is sent as a document. Multiple files are sent as document media groups, split at Telegram's maximum media
+group size. All sends enable Telegram's protected-content flag. The bot also prints its own account information at
+startup and prints polling exceptions.
+
+## Setup and security
+
+Create a bot with BotFather and obtain its token. Give the process read access to a dedicated directory containing only
+files that every bot user may receive, and pass that directory explicitly. The bot has no user or chat allowlist and no
+file-name or file-type filter; anyone able to send it the command can request files reachable through the configured
+tree. Protected content is not an access-control mechanism.
+
+Keep the token private. These launchers accept it on the command line, where it may be retained in shell history or be
+visible to other local processes. Also avoid roots containing secrets or links to locations outside the intended tree.
+
+## Arguments
+
+Both launchers interpret arguments in the same order:
+
+1. `BOT_TOKEN` (required). Omitting it fails immediately.
+2. `ROOT_PATH` (optional in code), either a file or directory. Relative paths are resolved from the process working
+   directory; use an explicit absolute path for predictable behavior. The launchers pass an empty path when this
+   argument is omitted, whose filesystem behavior differs by platform and is not a reliable working-directory default.
+
+Additional arguments are ignored.
+
+## Launch from the repository root
+
+### JVM
 
 ```bash
-../gradlew run --args="BOT_TOKEN[ optional/folder/path]"
+./gradlew :RandomFileSenderBot:runJvm --args="<BOT_TOKEN> /absolute/path/to/files"
 ```
+
+The JVM picker uses `java.io.File`. A missing, empty, or unreadable directory produces no selection and therefore causes
+a positive request to keep retrying.
+
+### Kotlin/Native
+
+The shared native configuration selects Linux x64, Linux Arm64, or Windows x64 for the current host. macOS is not
+configured. Link the debug executable with Gradle, then pass the arguments directly to the generated program:
+
+```bash
+./gradlew :RandomFileSenderBot:linkDebugExecutableNative
+./RandomFileSenderBot/build/bin/native/debugExecutable/RandomFileSenderBot.kexe "<BOT_TOKEN>" "/absolute/path/to/files"
+```
+
+On Windows, run
+`RandomFileSenderBot\build\bin\native\debugExecutable\RandomFileSenderBot.exe "<BOT_TOKEN>" "C:\path\to\files"`
+after the same Gradle link task. The native picker uses Okio; unlike the JVM picker, inaccessible or invalid paths may
+raise a filesystem exception that is printed by the polling exception handler.
+
+## Source sets
+
+- `commonMain` contains the picker contract and the long-polling bot behavior.
+- `jvmMain` implements recursive selection with `java.io.File` and provides the suspending JVM entry point.
+- `nativeMain` implements recursive selection with Okio and provides a `runBlocking` native entry point.