refactor(core)!: rename Provider to LLMProvider and update implementations

- Export `LLMProvider` from `owlen-core` and replace public `Provider` re-exports.
- Convert `OllamaProvider` to implement the new `LLMProvider` trait with associated future types.
- Adjust imports and trait bounds in `remote_client.rs` to use the updated types.
- Add comprehensive provider interface tests (`provider_interface.rs`) verifying router routing and provider registry model listing with `MockProvider`.
- Align dependency versions across workspace crates by switching to workspace-managed versions.
- Extend CI (`.woodpecker.yml`) with a dedicated test step and generate coverage reports.
- Update architecture documentation to reflect the new provider abstraction.

crates/owlen-core/src/lib.rs

@@ -42,7 +42,7 @@ pub use mcp::{
 pub use mode::*;
 pub use model::*;
 // Export provider types but exclude test_utils to avoid ambiguity
-pub use provider::{ChatStream, Provider, ProviderConfig, ProviderRegistry};
+pub use provider::{ChatStream, LLMProvider, Provider, ProviderConfig, ProviderRegistry};
 pub use router::*;
 pub use sandbox::*;
 pub use session::*;