fix(frontend): replace hardcoded model ref with SSOT config (#2480)

[mrveiss]

Summary

• Replaces hardcoded llama3.2:1b model reference with getConfig().llm.defaultModel from SSOT config
• Model now reads from VITE_LLM_DEFAULT_MODEL env var

Closes #2480

Test plan

• No remaining hardcoded model references in useEnvironmentAnalysis.ts
• Environment analysis composable still functions correctly
• TypeScript compiles without errors

[github-actions]

✅ SSOT Configuration Compliance: Passing

🎉 No hardcoded values detected that have SSOT config equivalents!