Expose governed model dependency execution

[enricopiovesan]

Summary

• Persist app model_dependencies in CLI-produced workspace registration state and load them into runtime app registrations.
• Add a governed runtime model dependency execution surface that resolves an app-declared inference interface, revalidates the selected local provider/model, invokes the existing Ollama-backed provider, and returns ModelResolutionEvidence with output.
• Update authoring docs and smoke checks so WASM agents no longer own provider-specific model API calls.

Governing Spec

• 045-governed-model-dependency-resolution
• 046-public-cli-app-registration
• 006-runtime-request-execution
• 004-spec-alignment-gate

Project Item

• Closes Expose governed model dependency execution to downstream WASM agents #494
• Project 1 item: PVTI_lADOEbiBt84Bbyp1zgxBoH8

Validation

• cargo test
• cargo clippy -- -D warnings
• bash scripts/ci/repository_checks.sh
• bash scripts/ci/wasm_agent_authoring_guide_smoke.sh
• git diff --check