feat: Implement Phase 5 Quest System (100% complete)

Add YAML-driven quest system with context-aware offering:

Core Implementation:
- Quest data models (Quest, QuestObjective, QuestReward, QuestTriggers)
- QuestService for YAML loading and caching
- QuestEligibilityService with level, location, and probability filtering
- LoreService stub (MockLoreService) ready for Phase 6 Weaviate integration

Quest Content:
- 5 example quests across difficulty tiers (2 easy, 2 medium, 1 hard)
- Quest-centric design: quests define their NPC givers
- Location-based probability weights for natural quest offering

AI Integration:
- Quest offering section in npc_dialogue.j2 template
- Response parser extracts [QUEST_OFFER:quest_id] markers
- AI naturally weaves quest offers into NPC conversations

API Endpoints:
- POST /api/v1/quests/accept - Accept quest offer
- POST /api/v1/quests/decline - Decline quest offer
- POST /api/v1/quests/progress - Update objective progress
- POST /api/v1/quests/complete - Complete quest, claim rewards
- POST /api/v1/quests/abandon - Abandon active quest
- GET /api/v1/characters/{id}/quests - List character quests
- GET /api/v1/quests/{quest_id} - Get quest details

Frontend:
- Quest tracker sidebar with HTMX integration
- Quest offer modal for accept/decline flow
- Quest detail modal for viewing progress
- Combat service integration for kill objective tracking

Testing:
- Unit tests for Quest models and serialization
- Integration tests for full quest lifecycle
- Comprehensive test coverage for eligibility service

Documentation:
- Reorganized docs into /docs/phases/ structure
- Added Phase 5-12 planning documents
- Updated ROADMAP.md with new structure

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

api/app/ai/templates/npc_dialogue.j2

@@ -92,6 +92,67 @@ Work these into the dialogue naturally - don't dump all information at once.
 Make it feel earned, like the NPC is opening up to someone they trust.
 {% endif %}
 
+{% if quest_offering_context and quest_offering_context.should_offer %}
+## QUEST OFFERING OPPORTUNITY
+The NPC has a quest to offer. Weave this naturally into the conversation.
+
+**Quest:** {{ quest_offering_context.quest_name }}
+**Quest ID:** {{ quest_offering_context.quest_id }}
+
+{% if quest_offering_context.offer_dialogue %}
+**How the NPC Would Present It:**
+{{ quest_offering_context.offer_dialogue }}
+{% endif %}
+
+{% if quest_offering_context.npc_quest_knowledge %}
+**What the NPC Knows About This Quest:**
+{% for fact in quest_offering_context.npc_quest_knowledge %}
+- {{ fact }}
+{% endfor %}
+{% endif %}
+
+{% if quest_offering_context.narrative_hooks %}
+**Narrative Hooks (use 1-2 naturally):**
+{% for hook in quest_offering_context.narrative_hooks %}
+- The NPC {{ hook }}
+{% endfor %}
+{% endif %}
+
+**IMPORTANT QUEST OFFERING RULES:**
+- Do NOT dump all quest information at once
+- Let the quest emerge naturally from conversation
+- If the player seems interested or asks about problems/work, offer the quest
+- If the player changes topic, don't force it - just mention hints
+- When you offer the quest, include this marker on its own line: [QUEST_OFFER:{{ quest_offering_context.quest_id }}]
+- The marker signals the UI to show a quest accept/decline option
+{% endif %}
+
+{% if lore_context and lore_context.has_content %}
+## Relevant World Knowledge
+The NPC may reference this lore if contextually appropriate:
+
+{% if lore_context.quest %}
+**Quest Background:**
+{% for entry in lore_context.quest[:2] %}
+- {{ entry.content | truncate_text(150) }}
+{% endfor %}
+{% endif %}
+
+{% if lore_context.regional %}
+**Local Knowledge:**
+{% for entry in lore_context.regional[:3] %}
+- {{ entry.content | truncate_text(100) }}
+{% endfor %}
+{% endif %}
+
+{% if lore_context.world %}
+**Historical Knowledge (if NPC would know):**
+{% for entry in lore_context.world[:2] %}
+- {{ entry.content | truncate_text(100) }}
+{% endfor %}
+{% endif %}
+{% endif %}
+
 {% if npc.relationships %}
 ## NPC Relationships (for context)
 {% for rel in npc.relationships %}