Add workspace integration tests

- Create tests/workspace_integration.rs with 10 database tests
- Export MockEmbeddings for use in integration tests
- Tests cover: read/write, append, nested paths, delete, memory ops,
  daily log, FTS search, hybrid search, list_all, system_prompt

Requires: DATABASE_URL=postgres://localhost/near_agent_test

Co-Authored-By: Claude Opus 4.5 <[email protected]>

src/workspace/embeddings.rs

@@ -214,19 +214,20 @@ impl EmbeddingProvider for OpenAiEmbeddings {
 }
 
 /// A mock embedding provider for testing.
-#[cfg(test)]
+///
+/// Generates deterministic embeddings based on text hash.
+/// Useful for unit and integration tests.
 pub struct MockEmbeddings {
     dimension: usize,
 }
 
-#[cfg(test)]
 impl MockEmbeddings {
+    /// Create a new mock embeddings provider with the given dimension.
     pub fn new(dimension: usize) -> Self {
         Self { dimension }
     }
 }
 
-#[cfg(test)]
 #[async_trait]
 impl EmbeddingProvider for MockEmbeddings {
     fn dimension(&self) -> usize {

src/workspace/mod.rs

@@ -48,7 +48,7 @@ mod search;
 
 pub use chunker::{ChunkConfig, chunk_document};
 pub use document::{MemoryChunk, MemoryDocument, WorkspaceEntry, paths};
-pub use embeddings::{EmbeddingProvider, OpenAiEmbeddings};
+pub use embeddings::{EmbeddingProvider, MockEmbeddings, OpenAiEmbeddings};
 pub use repository::Repository;
 pub use search::{SearchConfig, SearchResult};