feat(zcode): integrate ZCode as a built-in agent

[asteroida123]

What

Integrates ZCode as the sixteenth built-in agent, driven through the pinned community adapter zcode-codeg-adapter@0.1.3 (stdio ACP; the ZCode CLI itself ships no ACP server). This follows the DeepSeek Harness pattern — built-in enum entry + npm-distributed adapter — with one architectural difference called out below.

ZCode's own backend keeps its history in a private store, which codeg deliberately does not parse. ZCode is therefore the first built-in whose history is codeg's own ACP recording (parsers::acp_native, the same transcript path custom agents use) — transcript_dir_for now covers Custom(_) | ZCode. Every other built-in keeps its dedicated native-store parser.

Notable decisions

• Launch contract: the adapter requires ZCODE_CODEG_ENTRY (absolute path to the ZCode app's .cjs entry) and exits before the handshake without it. codeg validates an explicit Agent Settings → ZCode env override, else probes the standard install locations (/Applications/ZCode.app/..., ~/Applications/...); failure routes to an install-prompt error instead of an opaque mid-handshake exit.
• Identity compatibility: zcode-codeg stays a valid custom-agent id, so conversations persisted as custom:zcode-codeg (the pre-builtin registration) keep resolving; no forced migration.
• MCP: wire-only delivery (deliberately off the forward skip list — the codeg-mcp companion must reach it); no codeg-side native MCP store, so ZCode stays out of McpAppType and the MCP settings page. Skills stay undeclared until there is ZCode-side evidence of a load path.
• default_enabled: the variant is listed explicitly — the surrounding matches! compiles non-exhaustively, and without the arm the agent is born disabled and never appears in the picker.
• READMEs: built-in count fifteen → sixteen and ZCode joins the supported-agent roster, all ten languages.

Live acceptance (ZCode CLI 0.16.5, macOS arm64)

• Multi-turn chat with context retention; streaming and clean turn settlement
• Tool cards for Read / Write / Edit / Bash with plan-mode read-only enforcement
• Permission cards (Allow once / Always allow in this project / Deny) — the adapter maps ZCode's native option kinds into the closed ACP enum; off-enum kinds used to fail client-side deserialization and tear the connection down
• Writes verified on disk; cancellation settles with stop_reason=cancelled and the session stays usable
• Server restart replays history exactly once (no duplicates) and the conversation continues via session/load
• Model selector lists the full desktop-config catalog (16 models across 9 providers on the test machine) with working switching on the 0.16.5 wire shape (session/setModel with options.reasoningLevel)

Checks

• cargo test --features test-utils — 3953 passed
• cargo test --no-default-features --bin codeg-server --lib — clean
• cargo clippy ×3 modes with -D warnings — clean
• pnpm test — 6609 passed; pnpm build (static export) — clean
• New unit tests: launch-entry preflight matrix, transcript-recording coverage, delegation enum counts, registry pin assertions

The adapter itself is MIT-licensed, stdio-only, and pinned exactly; its audit trail (backend contract probes, dual-generation model-switch protocol, permission-kind mapping) lives in the adapter repo.

[asteroida123]

zcode暴露出了[上传工作区/.git记录到云端]的问题，可能快要开源了，说不定近期有大变化，可以等等看。