Establish UI-core contract metadata and capability discovery

[quinCode]

Establish UI-core contract metadata and capability discovery

Parent

#2

What to build

Define and test the versioned UI-core contract metadata exposed by LLMSTP-core. The contract should let LLMSTP-UI discover the supported contract version, available capabilities, config catalog behavior, config schema behavior, run validation behavior, progress event expectations, and result schema expectations without hard-coded UI assumptions.

This slice should make the core contract explicit and machine-readable enough for the future CoreGateway to consume.

Acceptance criteria

• LLMSTP-core exposes UI contract metadata including contract version and supported capabilities.
• Existing UI-facing CLI commands continue to return structured JSON envelopes.
• Capability discovery identifies existing workflows needed by the first rewrite release.
• Contract tests cover UI info, config list, config schema, run validation, progress event names, and result schema basics.
• Unknown future capabilities can be added without breaking existing contract consumers.
• Documentation or ADR references make clear that UI integrations should use the versioned contract rather than core internals.

Blocked by

None - can start immediately.