[Feature] Add Linux ARM architecture support for Android CLI

### Affected Skill
`devtools/android-cli`

### Description
The Android CLI currently does not provide a build for Linux ARM architecture (e.g., `linux_arm64`). This limits users who want to run the Android CLI directly on ARM-based Linux devices, such as:
- Mobile devices running Linux distributions (e.g., Ubuntu Touch, postmarketOS)
- ARM-based single-board computers (e.g., Raspberry Pi)
- Development on native Linux mobile environments

### Expected Behavior
The Android CLI installation should support Linux ARM architecture variants, similar to how it supports:
- `linux_x86_64`
- `darwin_arm64` (Mac ARM)
- `darwin_x86_64` (Mac Intel)
- `windows_x86_64`

### Actual Behavior
Installation commands only provide:
- Linux x86_64: `curl -fsSL https://dl.google.com/android/cli/latest/linux_x86_64/install.sh | bash`
- No Linux ARM variant available

### Steps to Reproduce
1. Attempt to install Android CLI on a Linux ARM device
2. No appropriate installation binary is available for the architecture
3. Users are unable to use the android-cli skill on ARM-based Linux systems

### Suggested Fix
Provide Linux ARM builds of the Android CLI, including:
- `linux_arm64` (for ARMv8/ARM64)
- Optionally: `linux_armv7` (for ARMv7)

And update the skill documentation and installation instructions to include these variants.

Start with the devtools/android-cli skill and trace how the existing linux_x86_64 installation command and platform variants are defined. Determine where Linux ARM builds are configured, then update the installation instructions for the supported ARM variants and verify that the resulting commands provide usable builds on Linux ARM devices.

Written by the indexing model from the issue text.