Add OpenCode Mobile (Development)

[OpenCodeEngineer]

Adds OpenCode Mobile to the Development section.

• Repo: https://github.com/dzianisv/opencode-mobile
• License: MIT (FOSS), full source available
• What it is: Open-source Android client for the opencode AI coding agent — connect to an opencode server you self-host and run AI coding sessions from your phone.

Criteria check:

• FOSS (MIT) with source available
• No ads, no spyware, no proprietary elements in the app
• Stable (v0.4.3) and actively developed
• Documentation/website: https://dzianisv.github.io/opencode-mobile/
• Free of charge
• Sorted alphabetically in Development

Note: the app connects to a user-self-hosted server (NonFreeNet anti-feature) which may reach proprietary AI APIs using the user's own keys; the app itself ships no proprietary code. F-Droid/IzzyOnDroid badges will be added once those listings land (mainline MR in review).