Implement actors, stats, effects, death, and respawn

[zoeyrose]

Outcome

Provide the minimum living-entity model for players and monsters while keeping derived values, timers, and lifecycle transitions deterministic and server-authoritative.

Scope and invariants

• Define base/derived stats, protections, resource pools, regeneration, movement capability, status effects, immunities, and stable effect-source attribution.
• Use typed modifier aggregation with explicit stacking/priority rules; never infer mechanics from client-visible text.
• Schedule durations and periodic effects on simulation time through the common action/event foundation.
• Implement damage/healing application, zero-health transition, death, corpse/loot handoff, respawn, disconnect, and persistence boundaries atomically.
• Project only authorized semantic state and timing to Game Protocol 1.

Acceptance criteria

• Tests cover modifier ordering, caps/overflow, regeneration, stacked effects, expiration, simultaneous lethal/healing events, repeated death, disconnect, respawn, and save/reload.
• Replay produces identical effects/death events and state digest.
• No domain owns a private timer loop or mutable stat cache outside the actor owner.
• A player and monster can participate in the M3 combat slice with bounded scene/protocol projection.
• Advanced disciplines and weather can extend typed modifiers without changing the core lifecycle.

Dependencies and parallelization

Depends on #32, #37, #39, and #41. Inventory equipment modifiers #49 and baseline combat #50 integrate through published interfaces.

Independent implementation

Implement from the preserved issue-level/product behavior and independently authored fixtures. Do not copy or mechanically translate GPL server/Python code or tests. Replacement code is MIT; consumed content and assets keep their own licenses.