Add SDK usage examples

12 examples showing increasing levels of customization:
- 01-minimal: all defaults
- 02-custom-model: model and thinking level
- 03-custom-prompt: replace or modify prompt
- 04-skills: discover, filter, merge skills
- 05-tools: built-in tools, custom tools
- 06-hooks: logging, blocking, result modification
- 07-context-files: AGENTS.md files
- 08-slash-commands: file-based commands
- 09-api-keys-and-oauth: API key resolution, OAuth config
- 10-settings: compaction, retry, terminal settings
- 11-sessions: persistence options
- 12-full-control: replace everything

Also exports FileSlashCommand type from index.ts

packages/coding-agent/examples/sdk/11-sessions.ts

@@ -0,0 +1,46 @@
+/**
+ * Session Management
+ *
+ * Control session persistence: in-memory, new file, continue, or open specific.
+ */
+
+import { createAgentSession, SessionManager } from "../../src/index.js";
+
+// In-memory (no persistence)
+const { session: inMemory } = await createAgentSession({
+	sessionManager: SessionManager.inMemory(),
+});
+console.log("In-memory session:", inMemory.sessionFile ?? "(none)");
+
+// New persistent session
+const { session: newSession } = await createAgentSession({
+	sessionManager: SessionManager.create(process.cwd()),
+});
+console.log("New session file:", newSession.sessionFile);
+
+// Continue most recent session (or create new if none)
+const { session: continued, modelFallbackMessage } = await createAgentSession({
+	sessionManager: SessionManager.continueRecent(process.cwd()),
+});
+if (modelFallbackMessage) console.log("Note:", modelFallbackMessage);
+console.log("Continued session:", continued.sessionFile);
+
+// List and open specific session
+const sessions = SessionManager.list(process.cwd());
+console.log(`\nFound ${sessions.length} sessions:`);
+for (const info of sessions.slice(0, 3)) {
+	console.log(`  ${info.id.slice(0, 8)}... - "${info.firstMessage.slice(0, 30)}..."`);
+}
+
+if (sessions.length > 0) {
+	const { session: opened } = await createAgentSession({
+		sessionManager: SessionManager.open(sessions[0].path),
+	});
+	console.log(`\nOpened: ${opened.sessionId}`);
+}
+
+// Custom session directory
+// const { session } = await createAgentSession({
+//   agentDir: "/custom/agent",
+//   sessionManager: SessionManager.create(process.cwd(), "/custom/agent"),
+// });