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-mcp-llm-server/Cargo.toml

@@ -6,11 +6,11 @@ edition = "2021"
 [dependencies]
 owlen-core = { path = "../owlen-core" }
 owlen-ollama = { path = "../owlen-ollama" }
-tokio = { version = "1.0", features = ["full"] }
-serde = { version = "1.0", features = ["derive"] }
-serde_json = "1.0"
-anyhow = "1.0"
-tokio-stream = "0.1"
+tokio = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }
+anyhow = { workspace = true }
+tokio-stream = { workspace = true }
 
 [[bin]]
 name = "owlen-mcp-llm-server"