docs(cerebro): write Running page EN/ES

[yacosta738]

Goal

Document how to run Cerebro: the two binary entry points, CLI flags, ports, health endpoint, and startup verification.

Scope

• Create src/content/docs/cerebro/running.md (EN)
• Create src/content/docs/es/cerebro/running.md (ES)
• Document cerebro serve (full CLI with migrate subcommands)
• Document cerebro-serve (lightweight server-only entry point)
• Cover bind address, port configuration, health check endpoint
• Include quick-start examples

Source Files

• modules/cerebro/src/bin/cerebro.rs — full CLI entry point
• modules/cerebro/src/main.rs — cerebro-serve binary
• modules/cerebro/src/server.rs — Axum HTTP/MCP router, health endpoint

Acceptance Criteria

• EN page exists with complete running documentation
• ES page exists with Spanish translation
• Both binaries documented with usage examples
• Health check endpoint documented
• make docs-check passes

[linear]

DALLAY-225