Add unit tests for untested game modules

[philippe-ths]

Summary

9 core game modules have zero unit tests. This parent issue tracks adding test coverage across two tiers based on effort and mocking requirements.

Quick wins (pure/near-pure functions)

• Add unit tests for MapData #35 — MapData
• Add unit tests for Pathfinder #36 — Pathfinder
• Add unit tests for WorldState #37 — WorldState
• Add unit tests for ToolRegistry #38 — ToolRegistry

Medium effort (requires mocking)

• Add unit tests for GoalManager #39 — GoalManager
• Add unit tests for DirectiveExecutor #40 — DirectiveExecutor
• Add unit tests for ConversationManager #41 — ConversationManager
• Add unit tests for ToolService #42 — ToolService

Context

Existing unit tests cover parsers, validation, and some services (LLMService, ChronologicalLog, GoalExtractor, ReflectionManager, FunctionBuilderService, PersistedFunctionAudit). The headless evaluation system provides some indirect integration coverage for several of these modules, but no targeted unit tests exist.

[philippe-ths]

All 4 quick-win sub-issues are complete:

• Add unit tests for MapData #35 MapData — 25 tests (PR test: add unit tests for MapData (#35) #43)
• Add unit tests for Pathfinder #36 Pathfinder — 14 tests (PR test: add unit tests for Pathfinder (#36) #44)
• Add unit tests for WorldState #37 WorldState — 13 tests (PR test: add unit tests for WorldState (#37) #45)
• Add unit tests for ToolRegistry #38 ToolRegistry — 12 tests (PR test: add unit tests for ToolRegistry (#38) #46)

Total: 64 new unit tests, all merged into test/untested-game-modules. Full suite at 94 tests, all passing.

Remaining: 4 medium-effort sub-issues (#39–#42).

[philippe-ths]

Tracked but deferred — leaving open for future work.