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).

Dockerfile

@@ -122,6 +122,14 @@ RUN ARCH=$(case "${TARGETARCH}" in amd64) echo "x86_64" ;; arm64) echo "aarch64"
     curl -fsSL "https://static.rust-lang.org/rustup/dist/${ARCH}-unknown-linux-gnu/rustup-init" -o /usr/local/bin/rustup-init && \
     chmod +x /usr/local/bin/rustup-init
 
+# gitea-mcp — MCP server for Gitea API (official, Go binary)
+ARG GITEA_MCP_VERSION=1.1.0
+RUN ARCH=$(case "${TARGETARCH}" in amd64) echo "x86_64" ;; arm64) echo "arm64" ;; *) echo "x86_64" ;; esac) && \
+    curl -fsSL "https://gitea.com/gitea/gitea-mcp/releases/download/v${GITEA_MCP_VERSION}/gitea-mcp_Linux_${ARCH}.tar.gz" \
+    | tar -xz -C /usr/local/bin/ gitea-mcp && \
+    chmod +x /usr/local/bin/gitea-mcp && \
+    gitea-mcp --version
+
 # Set locale — generate common UTF-8 locales (override via LANG/LC_ALL env vars)
 # To add more locales, run: sudo sed -i '/<locale>.UTF-8/s/^# //g' /etc/locale.gen && sudo locale-gen
 RUN sed -i -E '/(en_US|en_GB|sv_SE|da_DK|nb_NO|fi_FI|de_DE|fr_FR|es_ES|it_IT|pt_BR|nl_NL|pl_PL|ja_JP|ko_KR|zh_CN)\.UTF-8/s/^# //g' /etc/locale.gen && locale-gen