Cua Driver 0.12.6 compatibility fixtures

These fixtures lock selected stable public contract fields from the cua-driver-rs-v0.12.6 release tag at commit 9eb1f481b8a12cd6ffda2ad5af21653a9e5aa9e5.

The snapshots were derived from the release-tagged package sources, generated bindings, cua-driver --help, cua-driver manifest, and MCP JSON-RPC responses. The corresponding tests compare semantic fields instead of whole-process output. This intentionally excludes executable paths, socket paths, PIDs, session identifiers, platform-specific prose, and other volatile values. Release version fields are checked for their documented shape rather than frozen to 0.12.6, because a compatible later release must change them.

• python-package.json locks package-root exports and callable signatures.
• typescript-package.json locks package subpath exports, declaration exports, and the generated CuaDriver declaration methods.
• cli.json locks the CLI help header/catalog and selected manifest fields.
• mcp.json locks initialize, tools-list envelope/tool fields, and the method-not-found error category.
• apps/ contains unchanged Rust, Python, and TypeScript applications written against that baseline. CI compiles or executes them against candidate packages.

Additive manifest fields, tools, and package metadata are permitted. Removing or changing an item recorded here requires an explicit compatibility decision and an intentional fixture update.

RFC 2549 independently accepts one additive CLI change: cua-driver mcp --direct. Bare MCP behavior remains platform-defined (direct on Windows and Linux, signed app service on macOS), while --socket continues to select an explicit service. The semantic compatibility test permits that additive flag without rewriting the frozen cli.json baseline.