feat: Autonomous goal generation + creative synthesis engine

[Steake]

Context

The system can produce cognitive state metrics but cannot yet generate its own goals, pursue them autonomously, or synthesise novel creative outputs. This issue delivers the autonomous intentionality layer described in the Unified Consciousness Blueprint.

Tasks

• Implement AutonomousGoalGenerator — monitors cognitive state gaps and proposes goals without external prompting
• Implement CreativeSynthesisEngine — novel concept combination with aesthetic scoring
• Implement MetacognitiveReflectionEngine.enable_metacognitive_awareness() — full reflection loop, not stub
• Expose GET /api/consciousness/goals — returns active autonomous goals
• Wire goal generation output into the recursive prompt construction
• Tests: autonomous goals generated > 0 after 60s runtime, creative output novelty > 0.6

Acceptance

• System generates ≥1 autonomous goal per session without prompting
• Goals are coherent, relevant to active processing context
• Creative synthesis produces outputs rated novel by evaluator

Milestone: v0.5