Add official Gitea MCP server to base image

Install gitea-mcp v1.1.0 (Go binary from gitea.com/gitea/gitea-mcp)
using the same multi-arch pattern as gosu/fzf/bat. Provides 50+ MCP
tools for Gitea API — repos, issues, PRs, releases, branches, wiki,
and Actions.

Disabled by default in auto-generated opencode.json (requires
GITEA_ACCESS_TOKEN and GITEA_HOST to be useful). Users enable it by
setting those env vars in .env and flipping enabled to true in their
opencode.json.

Env vars forwarded into the container via docker-compose.yml and
docker-compose.shared.yml environment blocks. Same {env:VAR} pattern
as the GitHub MCP server.

Docs updated: README.md (new Gitea MCP section with setup steps),
DOCKER_HUB.md (tools list), CHANGELOG.md (v1.14.28b entry).

CHANGELOG.md

@@ -10,6 +10,7 @@ Tags follow `v{opencode_version}[letter]` — bare tag for the first build on a
 
 - **Feature:** Add MemPalace local-first AI memory system to base image. Provides 29 MCP tools for semantic search over conversation history, knowledge graph queries, and agent diaries. Palace data persists via optional `devbox-palace` named volume, ChromaDB embedding model cache via `devbox-chroma-cache`. No API keys required.
 - **Feature:** Auto-register mempalace MCP server in generated opencode.json (when mempalace is installed and config is auto-generated from OPENCODE_PROVIDER).
+- **Feature:** Add official Gitea MCP server (`gitea-mcp`) to base image. Provides 50+ MCP tools for Gitea API (repos, issues, PRs, releases, Actions). Disabled by default — requires `GITEA_ACCESS_TOKEN` and `GITEA_HOST` env vars.
 
 ## v1.14.28 — 2026-04-26