v1.6.3-unreleased: Sunstrider zone fixes, QuestieLearner icon preservation, migration, and Busted test suite

Code changes (13 files, +916/-171):
- ZoneDB integration: GetZoneId() converts uiMapId→areaId via ZoneDB reverse lookup
- MIN_CONFIDENCE_PINS reduced to 1 for Ascension (incomplete NPC DBs)
- QuestieLearner icon preservation: objective Icon passed to RegisterObjectiveTooltip
- InjectLearnedData zone migration: converts old uiMapId spawn keys to areaId
- areaId passed through all LearnNPC call sites (OnMouseoverUnit, OnQuestDetail,
  OnQuestComplete, OnQuestAccepted, OnQuestTurnedIn, OnGossipShow)
- Compat/Compat.lua: C_Map.GetPlayerMapPosition UiMapData support
- Compat/HBD.lua: Sunstrider mapData aliases and fallback loading
- Sunstrider arrow fix (QuestieArrow.lua), resolved pin rendering (QuestieMap.lua)
- _MergeOverride helper for string/numeric key compatibility
- Northshire Valley UiMapData registration

Testing infrastructure:
- .busted config pointing to tests/ directory
- Tests/wow_api_mock.lua: WoW API mocks (ZoneDB, C_Map, QuestLogCache, etc.)
- Tests/QuestieLearner_spec.lua: 12 tests covering coordinate scaling, spell cast
  learning, zone migration (NPC/objects), icon preservation, settings defaults,
  and LearnNPC spawn zone tracking
- selene.toml + wow_classic.yml: linter configuration

Documentation:
- Makefile with test/lint/ci targets
- sunstrider-coordinate-collection.md: coordinate data reference
- sunstrider-pin-fix.md: root cause analysis and fix documentation

Makefile

@@ -0,0 +1,26 @@
+# Makefile for Questie-X development tasks
+# Requires: lua5.1, busted, selene
+
+BUSTED   := busted
+SELENE   := selene
+
+.PHONY: test test-verbose lint ci clean
+
+# Run all Busted unit tests
+test:
+	$(BUSTED)
+
+# Run tests with verbose output
+test-verbose:
+	$(BUSTED) --verbose
+
+# Run selene linter with WoW Classic ruleset
+lint:
+	$(SELENE) --config selene.toml .
+
+# CI: run lint + test
+ci: lint test
+
+# Clean up temporary/generated files
+clean:
+	rm -f luac.out *.bak