feat(coding-agent): add session naming via /name command and extension API

- Add SessionInfoEntry type for session metadata
- Add /name <name> command to set session display name
- Add pi.setSessionName() and pi.getSessionName() extension API
- Session selector shows name (in warning color) instead of first message when set
- Session name included in fuzzy search
- /session command displays name when set

closes #650

packages/coding-agent/src/modes/interactive/components/session-selector.ts

@@ -130,7 +130,7 @@ class SessionList implements Component {
 		this.filteredSessions = fuzzyFilter(
 			this.allSessions,
 			query,
-			(session) => `${session.id} ${session.allMessagesText} ${session.cwd}`,
+			(session) => `${session.id} ${session.name ?? ""} ${session.allMessagesText} ${session.cwd}`,
 		);
 		this.selectedIndex = Math.min(this.selectedIndex, Math.max(0, this.filteredSessions.length - 1));
 	}
@@ -167,14 +167,24 @@ class SessionList implements Component {
 			const session = this.filteredSessions[i];
 			const isSelected = i === this.selectedIndex;
 
-			// Normalize first message to single line
-			const normalizedMessage = session.firstMessage.replace(/\n/g, " ").trim();
+			// Use session name if set, otherwise first message
+			const hasName = !!session.name;
+			const displayText = session.name ?? session.firstMessage;
+			const normalizedMessage = displayText.replace(/\n/g, " ").trim();
 
 			// First line: cursor + message (truncate to visible width)
+			// Use warning color for custom names to distinguish from first message
 			const cursor = isSelected ? theme.fg("accent", "› ") : "  ";
 			const maxMsgWidth = width - 2; // Account for cursor (2 visible chars)
 			const truncatedMsg = truncateToWidth(normalizedMessage, maxMsgWidth, "...");
-			const messageLine = cursor + (isSelected ? theme.bold(truncatedMsg) : truncatedMsg);
+			let styledMsg = truncatedMsg;
+			if (hasName) {
+				styledMsg = theme.fg("warning", truncatedMsg);
+			}
+			if (isSelected) {
+				styledMsg = theme.bold(styledMsg);
+			}
+			const messageLine = cursor + styledMsg;
 
 			// Second line: metadata (dimmed) - also truncate for safety
 			const modified = formatSessionDate(session.modified);

packages/coding-agent/src/modes/interactive/interactive-mode.ts

@@ -286,6 +286,7 @@ export class InteractiveMode {
 			{ name: "export", description: "Export session to HTML file" },
 			{ name: "share", description: "Share session as a secret GitHub gist" },
 			{ name: "copy", description: "Copy last agent message to clipboard" },
+			{ name: "name", description: "Set session display name" },
 			{ name: "session", description: "Show session info and stats" },
 			{ name: "changelog", description: "Show changelog entries" },
 			{ name: "hotkeys", description: "Show all keyboard shortcuts" },
@@ -677,6 +678,12 @@ export class InteractiveMode {
 				appendEntry: (customType, data) => {
 					this.sessionManager.appendCustomEntry(customType, data);
 				},
+				setSessionName: (name) => {
+					this.sessionManager.appendSessionInfo(name);
+				},
+				getSessionName: () => {
+					return this.sessionManager.getSessionName();
+				},
 				getActiveTools: () => this.session.getActiveToolNames(),
 				getAllTools: () => this.session.getAllToolNames(),
 				setActiveTools: (toolNames) => this.session.setActiveToolsByName(toolNames),
@@ -1442,6 +1449,11 @@ export class InteractiveMode {
 				this.editor.setText("");
 				return;
 			}
+			if (text === "/name" || text.startsWith("/name ")) {
+				this.handleNameCommand(text);
+				this.editor.setText("");
+				return;
+			}
 			if (text === "/session") {
 				this.handleSessionCommand();
 				this.editor.setText("");
@@ -3258,10 +3270,34 @@ export class InteractiveMode {
 		}
 	}
 
+	private handleNameCommand(text: string): void {
+		const name = text.replace(/^\/name\s*/, "").trim();
+		if (!name) {
+			const currentName = this.sessionManager.getSessionName();
+			if (currentName) {
+				this.chatContainer.addChild(new Spacer(1));
+				this.chatContainer.addChild(new Text(theme.fg("dim", `Session name: ${currentName}`), 1, 0));
+			} else {
+				this.showWarning("Usage: /name <name>");
+			}
+			this.ui.requestRender();
+			return;
+		}
+
+		this.sessionManager.appendSessionInfo(name);
+		this.chatContainer.addChild(new Spacer(1));
+		this.chatContainer.addChild(new Text(theme.fg("dim", `Session name set: ${name}`), 1, 0));
+		this.ui.requestRender();
+	}
+
 	private handleSessionCommand(): void {
 		const stats = this.session.getSessionStats();
+		const sessionName = this.sessionManager.getSessionName();
 
 		let info = `${theme.bold("Session Info")}\n\n`;
+		if (sessionName) {
+			info += `${theme.fg("dim", "Name:")} ${sessionName}\n`;
+		}
 		info += `${theme.fg("dim", "File:")} ${stats.sessionFile ?? "In-memory"}\n`;
 		info += `${theme.fg("dim", "ID:")} ${stats.sessionId}\n\n`;
 		info += `${theme.bold("Messages")}\n`;