feat: initialize server structure and database schema

- Added initial server setup with Cargo.toml defining dependencies and project structure.
- Created build.rs for generating protobuf bindings and validating wire contracts.
- Established database schema with initial migration files for conversations, messages, and runs.
- Introduced tools and prompts for Cursor functionality, enhancing user interaction capabilities.

server/prompt/cursor/modes/plan.json

@@ -0,0 +1,7 @@
+{
+  "tools": [
+    "Shell", "Glob", "Grep", "Read", "TodoWrite", "ReadLints", "WebSearch",
+    "WebFetch", "AskQuestion", "CreatePlan", "Task", "FetchMcpResource",
+    "CallMcpTool", "SembleSearch", "SembleFindRelated"
+  ]
+}