[P3] Worker overlay sprites keyed by worker name — rendering collides at 11+ workers

[itsmiso-ai]

Problem: render_worker_overlay() keys its per-worker rendering state by worker name (worker_overlay_nodes, _overlay_sprite_cache_frame, _overlay_sprite_cache_carrying), but worker names are not unique at the population cap. recruit_worker() cycles names with current % Constants.WORKER_NAMES.size(), and the pool has exactly 10 entries — so the 11th worker (cap 12, reachable with 5 huts) duplicates "Jun", the 12th duplicates "Mara", etc. When two workers share a name they also share a single TextureRect: the second worker overwrites the sprite's position/frame, so both workers render at one location and animation frames are wrong. #242/#247 addressed duplicate names only up to 10 workers ("prevent name collisions when recruiting multiple workers") and test_recruit_unique_names only exercises 4 recruits, so the residual collision at 11+ is untested and unfixed.

Evidence:

• scripts/main.gd render_worker_overlay() — worker_overlay_nodes.has(name) returns the existing node for a duplicate name; _overlay_sprite_cache_frame[name] / _overlay_sprite_cache_carrying[name] gate texture assignment per name
• scripts/colony_sim.gd recruit_worker() — var next_index: int = current % Constants.WORKER_NAMES.size() (cycles; 11th recruit gets index 0)
• scripts/constants.gd:5 — WORKER_NAMES has 10 entries; WORKER_CAP_BONUSES = {"hut": 2} + BASE_WORKER_CAP = 2 -> cap 12 with 5 huts
• tests/test_recruit_worker.gd test_recruit_unique_names — asserts uniqueness only for range(4) recruits (cap 4)
• Commit 9b6553b (Expand WORKER_NAMES pool and add badge colors for all workers #242) — pool expansion to 10 was the intended fix for Expand WORKER_NAMES or add unique name generation #227; it does not cover the 11th+ worker

Acceptance:

• Overlay rendering is keyed by a stable per-worker identity (e.g., array index or a unique worker id), not name
• A sim/UI test with 12 workers (5 huts) shows every worker rendering at its own position with its own animation frame, including two workers named the same

[itsmiso-ai]

The issue clearly outlines the collision mechanism and provides solid evidence. When implementing, ensure the new keying strategy covers all three cache arrays (worker_overlay_nodes, _overlay_sprite_cache_frame, _overlay_sprite_cache_carrying) and update test_recruit_worker.gd to exercise the full 12-worker cap.