Runtime Scripts: embed piccolo with fuel and staged effects #317

This was generated by AI during triage.

Agent Brief

Category: enhancement
Summary: Add the contained Lua execution host and its failure boundary.

Current behavior:
Core has hook registries but no Runtime Script interpreter. The completed piccolo spike proves the chosen engine can run in the Module target.

Desired behavior:
Embed a pinned piccolo version behind one Runtime Script host interface. Cache compiled code only. Every invocation gets a fresh environment and a hard fuel budget. Host operations accumulate as staged effects. A successful invocation commits them through core gameplay operations. A syntax, runtime, or fuel failure discards every staged effect, records a bounded diagnostic, and lets the core tick and other Runtime Scripts continue.

Key interfaces:

• Runtime Script compiler cache
• Fresh invocation environment
• Fuel budget
• Staged-effect result

Acceptance criteria:

• Valid Lua compiles once and can run in multiple fresh invocations.
• Globals written in one invocation are absent from the next.
• An infinite loop exhausts fuel without stalling the tick.
• Any failure discards all effects staged by that invocation.
• A failed Runtime Script does not prevent later Runtime Scripts or core processing.
• Diagnostics identify script identity, event, and failure kind without unbounded output.

Out of scope:

• Persistent Lua globals
• Package reconciliation and event bindings
• A broad gameplay host API