feat(cli): add mcpctl config prime-agent — proxy MCP + skills sync for prime-agent

Mirror `mcpctl config claude` for prime-agent (which talks to the same mcpctl
proxy MCP gateway over HTTP instead of stdio):

`mcpctl config prime-agent --project X`:
- registers the proxy MCP gateway in ~/.prime/agent/settings.json as
  mcpServers.X = { type: "http", url: <gateway>/projects/X/mcp }, merging with
  any existing servers (e.g. the bundled `sre` project) and preserving all other
  settings
- writes a .mcpctl-project marker so later syncs resolve the project
- syncs the project's skills into ~/.prime/agent/skills/<name>/ as markdown
  skills (prime-agent auto-discovers them at session start)

New `mcpctl skills sync --agent prime-agent` target re-syncs the tree later.

- src/cli/src/config/prime-agent.ts: settings.json read/merge/write helpers
- src/cli/src/utils/prime-agent-skills.ts: prime-agent sync (reuses
  installSkillAtomic + skills-state; skips Claude-only hooks/postInstall)
- completes config.ts/skills.ts wiring; regenerated shell completions
- tests: commands/prime-agent.test.ts + utils/prime-agent-skills.test.ts

README.md

@@ -113,6 +113,37 @@ This writes a `.mcp.json` that tells Claude Code to connect through mcplocal. Re
 mcpctl console monitoring   # Preview what Claude sees
 ```
 
+### Connect prime-agent
+
+Prime-agent (Claude's open-source counterpart) talks to the same proxy MCP
+gateway over HTTP rather than stdio. Register a project and sync its skills
+into `~/.prime/agent/`:
+
+```bash
+mcpctl config prime-agent --project monitoring
+```
+
+This:
+
+1. Registers the proxy MCP gateway in `~/.prime/agent/settings.json` as
+   `mcpServers.monitoring = { "type": "http", "url": "https://mcp.ad.itaz.eu/projects/monitoring/mcp" }`
+   (merging with any existing servers — the bundled `sre` project is preserved).
+2. Writes a `.mcpctl-project` marker so later syncs resolve the project.
+3. Syncs the project's skills into `~/.prime/agent/skills/<name>/` as markdown
+   skills (prime-agent auto-discovers them at session start).
+
+Re-sync later with:
+
+```bash
+mcpctl skills sync --agent prime-agent --project monitoring
+```
+
+Preview the change without writing anything:
+
+```bash
+mcpctl config prime-agent --project monitoring --dry-run
+```
+
 ## Declarative Configuration
 
 Everything can be defined in YAML and applied with `mcpctl apply`: