Implements mcpctl as an opencode addon, mirroring the prime-agent UX
(active-project indicator + a /mcpctl project switcher). opencode is a
native MCP client, so instead of a bridge this mounts the active project's
proxy MCP gateway through opencode's own live MCP API.
- src/opencode-ext/mcpctl-opencode.ts — server plugin (headless runs): mounts
the active project under a stable `mcpctl` name via `client.mcp.add`,
re-asserting on first contact and before each turn; never throws.
- src/opencode-ext/mcpctl-opencode-tui.tsx — TUI plugin: `/mcpctl`,
`/mcpctl-status`, `/mcpctl-skills`, and a `mcpctl:<project>` indicator in
the prompt footer (next to the model name, above the token counter); the
switch delegates to the CLI then re-points the mount live.
- `mcpctl config opencode` — provision/reuse the project mcptoken, install +
register the plugins (tui.json), write the 0600 state file, sync skills.
- `skills sync --agent opencode` — new shared-tree target
(~/.config/opencode/skill).
- embedded-source generator + embed test, settings/config/order tests,
completions, README + docs/opencode-extension.md.
Typechecked against the real @opencode-ai/plugin types (1.18.15).
