Merge pull request #521 from opticon454/feat/mcp-sync

feat(mcp): sync MCP servers across enabled CLIs

# Conflicts:
#	src/config/cli-registry/schema.ts
#	src/config/cli-registry/types.ts
#	src/web/public/settings-ui.js

docs/cli-registry.md

@@ -253,6 +253,12 @@ A module-level const freezes at first import, and the failure is asymmetric: a C
 4. Only if it cannot install with a plain `npm install -g <pkg>`: give it a layer in `docker/agent.Dockerfile` and set `discovery.install.agentImageLayer: { kind: 'dedicated', reason }` on its entry in `stock.ts`. `test/docker-agent-image-coverage.test.ts` requires both, so an exclusion cannot quietly become an omission. An entry with no `npmPackage` needs only the Dockerfile layer, since it never enters the shared npm layer in the first place.
 5. That is usually all. If you find yourself wanting to add an `if` somewhere, the guard test will tell you — and the answer is a capability field, or a named profile if it genuinely needs to run code.
 
+## MCP server sync
+
+`capabilities.mcpConfig` (`{ path, format }`, `path` relative to the home directory) names the file a CLI keeps its user-level MCP server list in and the dialect it is written in. `src/mcp-sync.ts` reads that list from every ENABLED CLI that declares one, and that is installed or already has the file (a CLI that is neither is reported `absent`, never created), and adds any server a CLI is missing from the others. It writes other tools' own config, so it is **opt-in**: `mcpSyncEnabled` (synced, default OFF) gates `GET`/`POST /api/mcp-sync` (403 while off) and the Settings → Agents & CLIs → MCP servers controls. Declared today for claude, gemini, codex, opencode and antigravity; every format was checked against what the CLI's own `mcp add` writes, except opencode's (documented, not installed to check). A CLI with no entry (pi, grok, omp, deepseek) is not guessed at: it is listed as `unsupported` in the result when enabled. Adding one is a registry entry plus a small adapter in `mcp-sync.ts`, and a verified fixture in `test/mcp-sync.test.ts`.
+
+The rules the module keeps and the tests pin: it only ADDS (a name already defined, in any shape, is never edited or removed; a same-name difference is reported as a conflict); a server switched off in its own CLI is not copied; it never writes a file it could not parse (opencode JSONC with comments, a TOML file with a duplicate table) and re-parses the new text before writing; codex TOML is read with a real parser (`smol-toml`), so CRLF files and inline tables are handled; names such as `__proto__` are ignored and every table keyed by an untrusted name has no prototype; a symlinked config is written through, not replaced; a file that receives `env`/`headers` is left `0600`; only one apply runs at a time; and its result carries server names only, never env values or headers. The schema restricts `path` to a home-relative path without `..`, since sync writes to it.
+
 ## See also
 
 - [Agent CLIs](wiki/Agent-CLIs.md) — the user-facing per-CLI guide.