feat(ollama): enforce JSON logits & add nvim_buffer edit action

- Added format parameter to Ollama generate for JSON logit enforcement.

- Implemented safe edit action in nvim_buffer MCP tool to replace raw Lua.

server/src/handlers/workspaces.rs

@@ -359,7 +359,7 @@ impl McpTool for SemanticCodeSearchHandler {
             );
             if let Ok(summary) = state
                 .ollama
-                .generate(&prompt, None, Some("Respond clearly and concisely."))
+                .generate(&prompt, None, Some("Respond clearly and concisely."), None)
                 .await
             {
                 out.push_str("\n\n--- Local GraphRAG Summary ---\n");