fix(tools): override OpenCode HTTP-based session tools with local implementation

OpenCode v1.1.30+ added HTTP-based SessionList/Read/Search/Info tools that
require localhost:4096 server. Renamed our tools to PascalCase to override
them with local file-based implementation, fixing 'Unable to connect' errors.

src/tools/index.ts

@@ -65,8 +65,9 @@ export const builtinTools: Record<string, ToolDefinition> = {
   ast_grep_replace,
   grep,
   glob,
-  session_list,
-  session_read,
-  session_search,
-  session_info,
+  // Session tools - PascalCase to override OpenCode's built-in HTTP-based session tools
+  SessionList: session_list,
+  SessionRead: session_read,
+  SessionSearch: session_search,
+  SessionInfo: session_info,
 }