feat(web): optional activity-ordered sidebar

source/cydo/domain/storage/persistence.d

@@ -134,6 +134,11 @@ struct Persistence
 			"    has_messages INTEGER NOT NULL DEFAULT 1," ~
 			"    PRIMARY KEY (driver, profile_root, session_id)" ~
 			");",
+			// Migration 22: when the task was last actually worked on, as StdTime.
+			// Distinct from last_active, which is cleared on session start for
+			// crash recovery and so cannot survive a restart. Treated as a
+			// cache: recomputed from each transcript's tail at startup.
+			"ALTER TABLE tasks ADD COLUMN last_turn_at INTEGER NOT NULL DEFAULT 0;",
 		]);
 
 		// In CI, disable durability to speed up tests. This trades crash-safety
@@ -292,6 +297,7 @@ struct Persistence
 		long lastActive;
 		string entryPoint;
 		bool needsAttention;
+		long lastTurnAt;
 	}
 
 	TaskRow[] loadTasks()
@@ -300,11 +306,11 @@ struct Persistence
 		foreach (int tid, string agentSessionId, string description, string taskType,
 			int parentTid, string relationType, string workspace, string projectPath,
 			int worktreeTid, string taskStartHead, string title, string status, string agentName, int archived, string draft,
-			string resultText, long createdAt, long lastActive, string entryPoint, int needsAttention;
-			db.stmt!"SELECT tid, COALESCE(agent_session_id,''), COALESCE(description,''), COALESCE(task_type,'blank'), COALESCE(parent_tid,0), COALESCE(relation_type,''), COALESCE(workspace,''), COALESCE(project_path,''), COALESCE(worktree_tid,0), COALESCE(task_start_head,''), COALESCE(title,''), COALESCE(status,'completed'), COALESCE(agent_type,'claude'), COALESCE(archived,0), COALESCE(draft,''), COALESCE(result_text,''), COALESCE(created_at,0), COALESCE(last_active,0), COALESCE(entry_point,''), COALESCE(needs_attention,0) FROM tasks".iterate())
+			string resultText, long createdAt, long lastActive, string entryPoint, int needsAttention, long lastTurnAt;
+			db.stmt!"SELECT tid, COALESCE(agent_session_id,''), COALESCE(description,''), COALESCE(task_type,'blank'), COALESCE(parent_tid,0), COALESCE(relation_type,''), COALESCE(workspace,''), COALESCE(project_path,''), COALESCE(worktree_tid,0), COALESCE(task_start_head,''), COALESCE(title,''), COALESCE(status,'completed'), COALESCE(agent_type,'claude'), COALESCE(archived,0), COALESCE(draft,''), COALESCE(result_text,''), COALESCE(created_at,0), COALESCE(last_active,0), COALESCE(entry_point,''), COALESCE(needs_attention,0), COALESCE(last_turn_at,0) FROM tasks".iterate())
 		{
 			// tasks.agent_type stores the configured agent name from config.agents.
-			result ~= TaskRow(tid, agentSessionId, description, taskType, parentTid, relationType, workspace, projectPath, worktreeTid, taskStartHead, title, status, agentName, archived != 0, draft, resultText, createdAt, lastActive, entryPoint, needsAttention != 0);
+			result ~= TaskRow(tid, agentSessionId, description, taskType, parentTid, relationType, workspace, projectPath, worktreeTid, taskStartHead, title, status, agentName, archived != 0, draft, resultText, createdAt, lastActive, entryPoint, needsAttention != 0, lastTurnAt);
 		}
 		return result;
 	}
@@ -364,6 +370,11 @@ struct Persistence
 		db.stmt!"UPDATE tasks SET result_text = ? WHERE tid = ?".exec(resultText, tid);
 	}
 
+	void setLastTurnAt(int tid, long lastTurnAt)
+	{
+		db.stmt!"UPDATE tasks SET last_turn_at = ? WHERE tid = ?".exec(lastTurnAt, tid);
+	}
+
 	void setLastActive(int tid, long lastActive)
 	{
 		db.stmt!"UPDATE tasks SET last_active = ? WHERE tid = ?".exec(lastActive, tid);
@@ -610,7 +621,7 @@ unittest
 	int userVersion;
 	foreach (int value; persistence.db.stmt!"PRAGMA user_version".iterate())
 		userVersion = value;
-	assert(userVersion == 22);
+	assert(userVersion == 23);
 
 	auto rows = persistence.loadTasks();
 	assert(rows.length == 1);
@@ -629,7 +640,7 @@ unittest
 		"relation_type", "workspace", "project_path", "title", "status",
 		"worktree_path", "has_worktree", "agent_type", "archived", "draft",
 		"result_text", "created_at", "last_active", "worktree_tid", "entry_point",
-		"needs_attention", "task_start_head",
+		"needs_attention", "task_start_head", "last_turn_at",
 	]);
 
 	persistence.upsertSessionMetaCache("claude", "/profiles/one", "same-id", 1,

source/cydo/domain/tasks/model.d

@@ -557,6 +557,10 @@ struct TaskData
 	bool archived;
 	long createdAt;    // StdTime; 0 = not set
 	long lastActive;   // StdTime; 0 = not set
+	/// When this task was last actually worked on (StdTime), for recency
+	/// ordering. Unlike lastActive it is never cleared by session lifecycle,
+	/// and is recomputed from the transcript tail at startup.
+	long lastTurnAt;
 
 	/// Git repository root for the selected project.
 	/// Falls back to projectPath if git resolution fails.
@@ -1086,6 +1090,7 @@ struct TaskListEntry
 	string entry_point;
 	string agent_name;
 	string driver;  // resolved runtime driver ("claude"/"codex"/"copilot"); empty for orphaned agents
+	long last_turn_at;
 	bool archived;
 	bool archiving;  // true while an archive/unarchive transition is in progress
 	string draft;
@@ -1170,6 +1175,7 @@ struct ServerStatusMessage
 	bool auth_enabled;
 	bool dev_mode;
 	string build_id;
+	bool sidebar_sort_by_recency;
 }
 
 struct ScanStatusMessage

source/cydo/runtime/config/package.d

@@ -115,6 +115,11 @@ struct CydoConfig
 	@Optional bool dev_mode;
 	@Optional string log_level = "info";
 	@Optional string system_keyword = "SYSTEM";
+	/// Order the sidebar by activity rather than creation: the most recently
+	/// worked-on task sits at the top and the order updates as tasks are used,
+	/// a parent rising with its most recent descendant. Archive and Import move
+	/// below the live tasks. Off keeps the creation-ordered list.
+	@Optional bool sidebar_sort_by_recency;
 
 	/// Called by configy during parsing (configy/read.d:650), so a semantic
 	/// error surfaces on the same path as a YAML syntax error.

source/cydo/server/app.d

@@ -53,6 +53,7 @@ import cydo.workflow.history.native_history : ConfiguredNativeHistoryContext,
 	TaskHistoryResolution, TaskHistoryResolutionKind, UnavailableHistory,
 	UnavailableHistoryKind, resolveNativeHistoryContext;
 import cydo.workflow.history.abbrev : extractMessageText;
+import cydo.workflow.history.last_turn : lastTurnStdTime;
 import cydo.workflow.history.operations : CodexForkSourceState,
 	selectHistoryOperations;
 import cydo.runtime.logging : installRobustLogger;
@@ -873,6 +874,7 @@ class App
 			td.createdAt = row.createdAt;
 			td.lastActive = row.lastActive;
 			td.needsAttention = row.needsAttention;
+			td.lastTurnAt = row.lastTurnAt;
 			td.titleGenDone = row.title.length > 0;
 			auto rowTid = row.tid;
 			tasks[rowTid] = move(td);
@@ -960,6 +962,34 @@ class App
 			// Final fallback: if still no lastActive but has createdAt, use that
 			if (td.lastActive == 0 && td.createdAt != 0)
 				td.lastActive = td.createdAt;
+
+			// Recompute when the task was last actually worked on. Always, not
+			// just when unset: the stored value is a cache, and re-deriving it
+			// from the transcript keeps a task that went stale from staying
+			// stale until it happens to be used again. Resumes append session
+			// records rather than turns, so this steps over the restart.
+			if (td.agentSessionId.length > 0)
+			{
+				try
+				{
+					auto resolution = resolveTaskHistory(td.tid);
+					auto jp = resolution.kind == TaskHistoryResolutionKind.access
+						? resolution.requireAccess().path
+						: "";
+					if (jp.length > 0)
+					{
+						auto turnAt = lastTurnStdTime(jp);
+						if (turnAt != 0 && turnAt != td.lastTurnAt)
+						{
+							td.lastTurnAt = turnAt;
+							persistence.setLastTurnAt(td.tid, turnAt);
+						}
+					}
+				}
+				catch (Exception) {} // best-effort; falls back to createdAt below
+			}
+			if (td.lastTurnAt == 0)
+				td.lastTurnAt = td.createdAt;
 		}
 
 		discoveryService.enumerateSessions();
@@ -1136,6 +1166,7 @@ class App
 			authUser.length > 0 || authPass.length > 0,
 			config.dev_mode,
 			webDistDir,
+			config.sidebar_sort_by_recency,
 		).representation));
 		ws.send(Data(buildNoticesList(activeNotices).representation));
 		if (discoveryService.scanInProgress)
@@ -3434,6 +3465,7 @@ class App
 			authUser.length > 0 || authPass.length > 0,
 			config.dev_mode,
 			webDistDir,
+			config.sidebar_sort_by_recency,
 		));
 		infof("Config reloaded successfully");
 		discoveryService.endScan();
@@ -3523,7 +3555,12 @@ class App
 	private void touchTask(int tid)
 	{
 		import std.datetime : Clock;
-		tasks[tid].lastActive = Clock.currStdTime;
+		auto now = Clock.currStdTime;
+		tasks[tid].lastActive = now;
+		// real activity (a message sent, a turn finished), never session
+		// lifecycle, so this is safe to persist and survives restarts
+		tasks[tid].lastTurnAt = now;
+		persistence.setLastTurnAt(tid, now);
 	}
 
 	private AgentSession sessionForTask(int tid)

source/cydo/web/snapshots.d

@@ -23,7 +23,8 @@ TaskListEntry buildTaskEntry(ref TaskData td, size_t childCount, bool alive,
 		td.agentSessionId.length > 0 && !alive && td.status != "importable",
 		td.isProcessing, td.stdinClosed, canStop, td.needsAttention, td.hasPendingQuestion, td.notificationBody,
 		td.title, td.workspace, td.projectPath, td.parentTid, childCount, td.relationType, cast(string) td.status,
-		td.taskType, td.entryPoint, td.agentName, driver, td.archived, td.archiving, td.draft, td.error,
+		td.taskType, td.entryPoint, td.agentName, driver,
+		stdTimeToUnixMillis(td.lastTurnAt), td.archived, td.archiving, td.draft, td.error,
 		stdTimeToUnixMillis(td.createdAt), stdTimeToUnixMillis(td.lastActive));
 }
 
@@ -202,13 +203,15 @@ string readBuildId(string webDistDir)
 	return m[1].idup;
 }
 
-string buildServerStatus(bool authEnabled, bool devMode, string webDistDir)
+string buildServerStatus(bool authEnabled, bool devMode, string webDistDir,
+	bool sidebarSortByRecency = false)
 {
 	return toJson(ServerStatusMessage(
 		"server_status",
 		authEnabled,
 		devMode,
 		readBuildId(webDistDir),
+		sidebarSortByRecency,
 	));
 }
 
@@ -299,7 +302,7 @@ unittest
 	}
 
 	auto exact = buildTasksList([entry(1, 0, false, false, "completed", 2)], true);
-	assert(exact == `{"type":"tasks_list","complete":true,"tasks":[{"tid":1,"alive":false,"resumable":false,"isProcessing":false,"stdinClosed":false,"canStop":false,"needsAttention":false,"hasPendingQuestion":false,"notificationBody":null,"title":null,"workspace":null,"project_path":null,"parent_tid":0,"child_count":2,"relation_type":null,"status":"completed","task_type":null,"entry_point":null,"agent_name":null,"driver":null,"archived":false,"archiving":false,"draft":null,"error":null,"created_at":0,"last_active":0}]}`,
+	assert(exact == `{"type":"tasks_list","complete":true,"tasks":[{"tid":1,"alive":false,"resumable":false,"isProcessing":false,"stdinClosed":false,"canStop":false,"needsAttention":false,"hasPendingQuestion":false,"notificationBody":null,"title":null,"workspace":null,"project_path":null,"parent_tid":0,"child_count":2,"relation_type":null,"status":"completed","task_type":null,"entry_point":null,"agent_name":null,"driver":null,"last_turn_at":0,"archived":false,"archiving":false,"draft":null,"error":null,"created_at":0,"last_active":0}]}`,
 		exact);
 	assert(!exact.canFind(`"stage"`), exact);
 	assert(buildTasksList([], false).canFind(`"complete":false`));