docs(harnesses): note multi-harness orchestration is in beta

Add a short inline mention on the harnesses overview and the
multi-agent orchestration overview that mixing Warp Agent, Claude Code,
and Codex inside a single workflow is in beta and available to all
users. Kept low-key (no callouts, no separate section) per the existing
inline (beta) precedent on Deployment Patterns.

Co-Authored-By: Oz <oz-agent@warp.dev>

Author: hongyi-chen

src/content/docs/agent-platform/cloud-agents/harnesses/index.mdx

@@ -7,7 +7,7 @@ sidebar:
   label: "Overview"
 ---
 
-Oz can run third-party agents — [Claude Code](/agent-platform/cloud-agents/harnesses/claude-code/) and [Codex](/agent-platform/cloud-agents/harnesses/codex/) — as cloud agents alongside Warp Agent. You choose the harness (agent runtime) that fits the task; the platform around the run stays the same.
+Oz can run third-party agents — [Claude Code](/agent-platform/cloud-agents/harnesses/claude-code/) and [Codex](/agent-platform/cloud-agents/harnesses/codex/) — as cloud agents alongside Warp Agent. You choose the harness (agent runtime) that fits the task; the platform around the run stays the same. Multi-harness orchestration — using more than one harness in a single workflow — is in beta and available to all users.
 
 ## What stays the same
 

src/content/docs/agent-platform/cloud-agents/orchestration/index.mdx

@@ -27,7 +27,7 @@ The parent and child don't have to run in the same place. Orchestration supports
 * **Cloud → cloud** - a cloud parent spawns cloud children that each run in their own environment. This is the canonical pattern for review swarms, large fan-outs, and any orchestration triggered from Slack, Linear, a schedule, or the API.
 * **Cloud → cloud-local** - a cloud parent spawns children that run inside the parent's own cloud environment, rather than each child getting its own environment. Useful when children need to share state with the parent (a filesystem, a long-running process, a shell session) or when spinning up an environment per child would be wasteful.
 
-Children can also run with a different agent runtime than the parent. A parent running with the default Warp Agent can spawn children that run with [Claude Code](/agent-platform/cli-agents/claude-code/) or [Codex](/agent-platform/cli-agents/codex/), and vice versa.
+Children can also run with a different agent runtime than the parent. A parent running with the default Warp Agent can spawn children that run with [Claude Code](/agent-platform/cli-agents/claude-code/) or [Codex](/agent-platform/cli-agents/codex/), and vice versa. Multi-harness orchestration is in beta and available to all users.
 
 ## Run state transitions