FIX [SCMS] Normalize env + DB handling, add safe auto-seed on dev boot

[AdaInTheLab]

Normalize env + DB handling, add safe auto-seed on dev boot

This PR started as “why won’t the CLI behave?” and evolved into a full cleanup and hardening of environment handling, database safety, and dev startup ergonomics.

The result is a deterministic, safer backend with improved developer experience and zero risk of accidental DB misuse.

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✨ What changed

Environment handling

• Centralized environment loading in src/env.ts
• Normalized NODE_ENV to development | test | production
• Added lightweight runtime env validation (Zod-style, no dependency)
• Fail-fast behavior for invalid or dangerous configurations

Database safety

• Single source of truth for DB path resolution
• Deterministic DB selection per environment:
  • development → lab.dev.db
  • test → :memory:
  • production → lab.db
• Guardrails preventing test or dev from touching prod data
• Auto-create DB directories when missing (SQLite-safe)

Seeding improvements

• Updated seed script to align with current schema:
  • created_at / updated_at
  • coherence_score
  • optional content fields
• Idempotent inserts
• Refuses to run in test
• Refuses to run in production unless explicitly allowed

Auto-seed on dev boot

• On app startup:
  • Runs only in development
  • Runs only if DB is empty
  • Executes after schema bootstrap
• Removes manual setup friction without risking prod or test environments

Dev ergonomics

• Clean, predictable dev startup flow
• Instant health check visibility on boot
• Reduced “it works on my machine” edge cases
• IDE/browser tooling clarified to avoid cache/session bleed

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🛡️ Why this matters

• Eliminates ENV ambiguity (local, dev, etc.)
• Prevents accidental DB spills across environments
• Aligns schema ↔ seed ↔ models ↔ API
• Makes development startup reliable, repeatable, and fast
• Establishes a safer foundation for future features

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🦝 Notes

This work was born out of debugging CLI and IDE behavior, but resulted in meaningful infrastructure improvements and clearer system boundaries. Consider this a small internal reset that pays dividends going forward.