Add temporal versioning for node history tracking (Milestone 1)

Enable time-travel queries and history viewing by creating immutable
version records on every node update. Includes database schema changes,
store functions, MCP tools, and CLI commands for viewing history,
comparing versions, and restoring to previous states.

src/cli/index.ts

@@ -11,6 +11,9 @@ import { graphCommand } from './commands/graph';
 import { serveCommand } from './commands/serve';
 import { decayCommand } from './commands/decay';
 import { childrenCommand } from './commands/children';
+import { historyCommand } from './commands/history';
+import { diffCommand } from './commands/diff';
+import { restoreCommand } from './commands/restore';
 import { closeDb } from '../core/db';
 
 const program = new Command();
@@ -31,6 +34,9 @@ program.addCommand(graphCommand);
 program.addCommand(serveCommand);
 program.addCommand(decayCommand);
 program.addCommand(childrenCommand);
+program.addCommand(historyCommand);
+program.addCommand(diffCommand);
+program.addCommand(restoreCommand);
 
 program.hook('postAction', () => {
   closeDb();