refactor: finish companion rename migration

Complete the remaining pi-to-companion rename across companion-os, web, vm-orchestrator, docker, and archived fixtures.

Verification:
- semantic rg sweeps for Pi/piConfig/getPi/.pi runtime references
- npm run check in apps/companion-os (fails in this worktree: biome not found)

Co-authored-by: Codex <noreply@openai.com>

packages/coding-agent/docs/termux.md

@@ -1,6 +1,6 @@
 # Termux (Android) Setup
 
-Pi runs on Android via [Termux](https://termux.dev/), a terminal emulator and Linux environment for Android.
+Companion 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 pi
-npm install -g @mariozechner/pi-coding-agent
+# Install companion
+npm install -g @mariozechner/companion-coding-agent
 
 # Create config directory
-mkdir -p ~/.pi/agent
+mkdir -p ~/.companion/agent
 
-# Run pi
-pi
+# Run companion
+companion
 ```
 
 ## 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 `~/.pi/agent/AGENTS.md` to help the agent understand the Termux environment:
+Create `~/.companion/agent/AGENTS.md` to help the agent understand the Termux environment:
 
 ````markdown
 # Agent Environment: Termux on Android