refactor(vm): unify host runtime lifecycle

[fffonion]

Summary

• Unifies operation registration, cancellation, deadlines, resource ownership, cleanup, and VM reset behavior.
• Retains the single OperationRegistry / CancellationToken control plane.
• Migrates IO and SQLite lifecycle ownership without introducing HTTP transport in this layer.

Stack

• Base: refactor(compiler): build semantic module graph #15
• Next: refactor(host): bind capabilities and async execution #18

Verification

• Runtime context: 24 passed
• Runtime host: 4 passed
• SQLite host: 19 passed
• Workspace all-features compile and strict Clippy passed