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>

skills/spawn-issues/SKILL.md

@@ -3,7 +3,7 @@ name: spawn-issues
 description: >
   Orchestrate parallel issue implementation with automated review cycles. Use when
   implementing multiple issues concurrently, or when user says /spawn-issues.
-model: haiku
+model: claude-haiku-4-5
 argument-hint: <issue-number> [<issue-number>...]
 user-invocable: true
 ---