chore: rebrand companion-os to clanker-agent

- Rename all package names from companion-* to clanker-*
- Update npm scopes from @mariozechner to @harivansh-afk
- Rename config directories .companion -> .clanker
- Rename environment variables COMPANION_* -> CLANKER_*
- Update all documentation, README files, and install scripts
- Rename package directories (companion-channels, companion-grind, companion-teams)
- Update GitHub URLs to harivansh-afk/clanker-agent
- Preserve full git history from companion-cloud monorepo

packages/coding-agent/docs/termux.md

@@ -1,6 +1,6 @@
 # Termux (Android) Setup
 
-Companion runs on Android via [Termux](https://termux.dev/), a terminal emulator and Linux environment for Android.
+Clanker runs on Android via [Termux](https://termux.dev/), a terminal emulator and Linux environment for Android.
 
 ## Prerequisites
 
@@ -16,14 +16,14 @@ pkg update && pkg upgrade
 # Install dependencies
 pkg install nodejs termux-api git
 
-# Install companion
-npm install -g @mariozechner/companion-coding-agent
+# Install clanker
+npm install -g @mariozechner/clanker-coding-agent
 
 # Create config directory
-mkdir -p ~/.companion/agent
+mkdir -p ~/.clanker/agent
 
-# Run companion
-companion
+# Run clanker
+clanker
 ```
 
 ## Clipboard Support
@@ -34,7 +34,7 @@ Image clipboard is not supported on Termux (the `ctrl+v` image paste feature wil
 
 ## Example AGENTS.md for Termux
 
-Create `~/.companion/agent/AGENTS.md` to help the agent understand the Termux environment:
+Create `~/.clanker/agent/AGENTS.md` to help the agent understand the Termux environment:
 
 ````markdown
 # Agent Environment: Termux on Android