SDK: Promote catalogue search and planning APIs to stable

[gokhanarkan]

Summary

Promote the generated catalogue search and planning surface from preview to a stable Copilot SDK release using an exact schema-bearing CLI package.

Parent: #2106
Epic: https://github.com/github/copilot-ecosystem/issues/1230

Current state

SDK preview 1.0.12-preview.0 already contains generated catalog.search and mcp.planInstall types. Stable 1.0.11 does not. Apply remains blocked on runtime implementation.

Acceptance criteria

• Code generation consumes an exact verified CLI/platform package version.
• Node, Python, Go, .NET, Rust, and Java compile with the generated unions.
• searchId, capabilities, handles, and typed authentication failures round-trip without message matching.
• Search/plan separation and host confirmation requirements are documented.
• No convenience plan-and-apply wrapper is introduced.
• Stable release and artefact smoke results are recorded; apply remains explicitly unavailable until regenerated later.