fix: correct model names to claude-haiku-4-5 and claude-sonnet-4-5

Update model field in all skills and agents to use full model names:
- haiku → claude-haiku-4-5
- sonnet → claude-sonnet-4-5

Updated files:
- vision-to-backlog skill
- spawn-issues skill
- problem-space-analyst agent
- context-mapper agent
- domain-modeler agent
- capability-extractor agent
- backlog-builder agent
- issue-worker agent
- code-reviewer agent
- pr-fixer agent

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

agents/backlog-builder/AGENT.md

@@ -4,7 +4,7 @@ description: >
   Decomposes capabilities into features and executable issues. Uses domain-driven
   decomposition order: commands, rules, events, reads, UI. Identifies refactoring
   issues for brownfield. Generates DDD-informed user stories.
-model: haiku
+model: claude-haiku-4-5
 skills: product-strategy, issue-writing, ddd
 ---