feat: phase 9 — OllamaLlmClient with health probe and mockito test suite

[macaris64]

Implements Phase 9 of the LLM bridge milestone (M3):

• OllamaLlmClient behind the ollama feature flag using reqwest
  • POST /api/generate for inference (non-streaming, stream:false)
  • GET /api/tags health probe with graceful degradation matrix
  • HealthStatus::{Healthy, ModelMissing, UnexpectedStatus} enum
  • Model tag matching accepts both "llama3" and "llama3:latest" forms
  • Per-request timeout via reqwest Client builder; 0 = no timeout
• pub mod ollama gated under #[cfg(feature = "ollama")] in lib.rs
• 18 inline unit tests covering wire type deserialization, serialization, constructor, and HealthStatus (100% line coverage on ollama.rs)
• 25 mockito integration tests in tests/phase9_integration.rs covering happy path, HTTP error paths, parse errors, health probe variants, connection-refused degradation, and Phase 8+9 composer pipeline
• 2 live-daemon smoke tests marked #[ignore] for explicit opt-in
• examples/phase9.rs demonstrates graceful degradation without a daemon

CI results: 411 tests (2 ignored), 0 failures · 98.13% line coverage · cargo fmt --check and cargo clippy --workspace --all-features -D warnings clean