Add the FSM contract sample: one asset, 1000 instances #22

Current State

State machines are the adversarial case for a graph core: they require cycles, typed triggers instead of strings, and many concurrent instances of one asset. This sample proves the core has no DAG assumption and that the asset/instance split holds under load.

Tasks:

• Headless FSM sample with cyclic states, self-transitions and typed triggers
• One asset driving 1000 concurrent instances with independent state and timers
• Allocation measurement over repeated ticks as a permanent regression test
• Interpreter and compiled results compared by the differential harness

Acceptance Criteria:

• 1 asset, 1000 concurrent instances, zero per-tick allocations
• Renaming a trigger through the registry keeps saved assets loading
• Interpreter and compiled results are equal

Related:

• Epic: sample triad as API contract tests #5 (sample epic), Add MASS4.Graph.State: cycles, typed triggers and per-instance state #15, Add a differential test harness comparing backends with the interpreter #18
• Validate Graphs with a state-machine editor sample Guinevere#224 (editor-side FSM sample)