task: implement stats command

- Add 'task stats' command to show task statistics - Display total
tasks, status breakdown (open/in-progress/done) - Show epic count,
ready vs blocked tasks - Show task counts by priority (P0-P4) and
namespace - Support both human-readable and JSON output (--json flag)
- Add tests for stats command and stats --json - TaskStats data type
with ToJSON/FromJSON instances

All 31 tests passing.

Amp-Thread-ID:
https://ampcode.com/threads/T-4e6225cf-3e78-4538-963c-5377bbbccee8
Co-authored-by: Amp <amp@ampcode.com>

4 files changed, 112 insertions, 9 deletions

diff --git a/.tasks/tasks-test.jsonl b/.tasks/tasks-test.jsonl
deleted file mode 100644
index 0b6b854..0000000
--- a/.tasks/tasks-test.jsonl
+++ /dev/null
@@ -1,8 +0,0 @@
-{"taskCreatedAt":"2025-11-14T04:30:59.204565135Z","taskDependencies":[],"taskId":"t-hKlXQS","taskNamespace":null,"taskParent":null,"taskStatus":"Open","taskTitle":"Test task","taskType":"WorkTask","taskUpdatedAt":"2025-11-14T04:30:59.204565135Z"}
-{"taskCreatedAt":"2025-11-14T04:30:59.217052707Z","taskDependencies":[],"taskId":"t-hKm16i","taskNamespace":null,"taskParent":null,"taskStatus":"Open","taskTitle":"Test task for list","taskType":"WorkTask","taskUpdatedAt":"2025-11-14T04:30:59.217052707Z"}
-{"taskCreatedAt":"2025-11-14T04:30:59.218106749Z","taskDependencies":[],"taskId":"t-hKm1nj","taskNamespace":null,"taskParent":null,"taskStatus":"Open","taskTitle":"First task","taskType":"WorkTask","taskUpdatedAt":"2025-11-14T04:30:59.218106749Z"}
-{"taskCreatedAt":"2025-11-14T04:30:59.218343902Z","taskDependencies":[{"depId":"t-hKm1nj","depType":"Blocks"}],"taskId":"t-hKm1r8","taskNamespace":null,"taskParent":null,"taskStatus":"Open","taskTitle":"Blocked task","taskType":"WorkTask","taskUpdatedAt":"2025-11-14T04:30:59.218343902Z"}
-{"taskCreatedAt":"2025-11-14T04:30:59.219138111Z","taskDependencies":[],"taskId":"t-hKm1DW","taskNamespace":null,"taskParent":null,"taskStatus":"Open","taskTitle":"Original task","taskType":"WorkTask","taskUpdatedAt":"2025-11-14T04:30:59.219138111Z"}
-{"taskCreatedAt":"2025-11-14T04:30:59.219366383Z","taskDependencies":[{"depId":"t-hKm1DW","depType":"DiscoveredFrom"}],"taskId":"t-hKm1HD","taskNamespace":null,"taskParent":null,"taskStatus":"Open","taskTitle":"Discovered work","taskType":"WorkTask","taskUpdatedAt":"2025-11-14T04:30:59.219366383Z"}
-{"taskCreatedAt":"2025-11-14T04:30:59.220105422Z","taskDependencies":[],"taskId":"t-hKm1Ty","taskNamespace":null,"taskParent":null,"taskStatus":"Open","taskTitle":"Task A","taskType":"WorkTask","taskUpdatedAt":"2025-11-14T04:30:59.220105422Z"}
-{"taskCreatedAt":"2025-11-14T04:30:59.220248713Z","taskDependencies":[{"depId":"t-hKm1Ty","depType":"Related"}],"taskId":"t-hKm1VR","taskNamespace":null,"taskParent":null,"taskStatus":"Open","taskTitle":"Task B","taskType":"WorkTask","taskUpdatedAt":"2025-11-14T04:30:59.220248713Z"}
diff --git a/.tasks/tasks.jsonl b/.tasks/tasks.jsonl
index 10715dd..4dfc413 100644
--- a/.tasks/tasks.jsonl
+++ b/.tasks/tasks.jsonl
@@ -15,7 +15,7 @@
 {"taskCreatedAt":"2025-11-09T13:05:06.746734115Z","taskDependencies":[],"taskId":"t-PpZ6JC","taskNamespace":"Omni/Task.hs","taskParent":null,"taskPriority":"P2","taskStatus":"Open","taskTitle":"Add child_counters storage","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T13:05:06.746734115Z"}
 {"taskCreatedAt":"2025-11-09T13:05:06.774903465Z","taskDependencies":[],"taskId":"t-PpZe3X","taskNamespace":"Omni/Task.hs","taskParent":null,"taskPriority":"P2","taskStatus":"Open","taskTitle":"Update createTask to auto-generate child IDs","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T13:05:06.774903465Z"}
 {"taskCreatedAt":"2025-11-09T13:05:06.802295008Z","taskDependencies":[],"taskId":"t-PpZlbL","taskNamespace":"Omni/Task.hs","taskParent":null,"taskPriority":"P2","taskStatus":"Done","taskTitle":"Implement task tree visualization command","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T13:47:12.411364105Z"}
-{"taskCreatedAt":"2025-11-09T13:05:06.829842253Z","taskDependencies":[],"taskId":"t-PpZsm4","taskNamespace":"Omni/Task.hs","taskParent":null,"taskPriority":"P2","taskStatus":"Open","taskTitle":"Implement task stats command","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T13:05:06.829842253Z"}
+{"taskCreatedAt":"2025-11-09T13:05:06.829842253Z","taskDependencies":[],"taskId":"t-PpZsm4","taskNamespace":"Omni/Task.hs","taskParent":null,"taskPriority":"P2","taskStatus":"Done","taskTitle":"Implement task stats command","taskType":"WorkTask","taskUpdatedAt":"2025-11-20T19:05:37.772094417Z"}
 {"taskCreatedAt":"2025-11-09T13:05:06.85771202Z","taskDependencies":[],"taskId":"t-PpZzBA","taskNamespace":"Omni/Task.hs","taskParent":null,"taskPriority":"P2","taskStatus":"Open","taskTitle":"Implement epic progress tracking","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T13:05:06.85771202Z"}
 {"taskCreatedAt":"2025-11-09T13:05:06.88583862Z","taskDependencies":[],"taskId":"t-PpZGVf","taskNamespace":"Omni/Task.hs","taskParent":null,"taskPriority":"P2","taskStatus":"Done","taskTitle":"Add filtering by type and parent (list improvements)","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T13:17:51.373969453Z"}
 {"taskCreatedAt":"2025-11-09T13:05:18.344932105Z","taskDependencies":[],"taskId":"t-PqLLXk","taskNamespace":"Omni/Task.hs","taskParent":null,"taskPriority":"P2","taskStatus":"Done","taskTitle":"Implement epic and task types","taskType":"WorkTask","taskUpdatedAt":"2025-11-09T13:05:18.406381682Z"}
diff --git a/Omni/Task.hs b/Omni/Task.hs
index 6d2da71..bbb78bb 100644
--- a/Omni/Task.hs
+++ b/Omni/Task.hs
@@ -45,6 +45,7 @@ Usage:
   task update <id> <status> [--json]
   task deps <id> [--json]
   task tree [<id>] [--json]
+  task stats [--json]
   task export [--flush]
   task import -i <file>
   task sync
@@ -60,6 +61,7 @@ Commands:
   update                        Update task status
   deps                          Show dependency tree
   tree                          Show task tree (epics with children, or all epics if no ID given)
+  stats                         Show task statistics
   export                        Export and consolidate tasks to JSONL
   import                        Import tasks from JSONL file
   sync                          Export and commit tasks to git (does NOT push)
@@ -227,6 +229,12 @@ move args
           tree <- getTaskTree maybeId
           outputJson tree
         else showTaskTree maybeId
+  | args `Cli.has` Cli.command "stats" = do
+      if isJsonMode args
+        then do
+          stats <- getTaskStats
+          outputJson stats
+        else showTaskStats
   | args `Cli.has` Cli.command "export" = do
       exportTasks
       putText "Exported and consolidated tasks to .tasks/tasks.jsonl"
@@ -454,6 +462,18 @@ cliTests =
         case result of
           Left err -> Test.assertFailure <| "Failed to parse 'sync': " <> show err
           Right args -> args `Cli.has` Cli.command "sync" Test.@?= True,
+      Test.unit "stats command" <| do
+        let result = Docopt.parseArgs help ["stats"]
+        case result of
+          Left err -> Test.assertFailure <| "Failed to parse 'stats': " <> show err
+          Right args -> args `Cli.has` Cli.command "stats" Test.@?= True,
+      Test.unit "stats with --json flag" <| do
+        let result = Docopt.parseArgs help ["stats", "--json"]
+        case result of
+          Left err -> Test.assertFailure <| "Failed to parse 'stats --json': " <> show err
+          Right args -> do
+            args `Cli.has` Cli.command "stats" Test.@?= True
+            args `Cli.has` Cli.longOption "json" Test.@?= True,
       Test.unit "create with flags in different order" <| do
         let result = Docopt.parseArgs help ["create", "Test", "--json", "--priority=1", "--namespace=Omni/Task"]
         case result of
diff --git a/Omni/Task/Core.hs b/Omni/Task/Core.hs
index f463040..e9da38e 100644
--- a/Omni/Task/Core.hs
+++ b/Omni/Task/Core.hs
@@ -437,6 +437,97 @@ exportTasks = do
   TIO.writeFile tasksFile ""
   traverse_ saveTask tasks
 
+-- Task statistics
+data TaskStats = TaskStats
+  { totalTasks :: Int,
+    openTasks :: Int,
+    inProgressTasks :: Int,
+    doneTasks :: Int,
+    totalEpics :: Int,
+    readyTasks :: Int,
+    blockedTasks :: Int,
+    tasksByPriority :: [(Priority, Int)],
+    tasksByNamespace :: [(Text, Int)]
+  }
+  deriving (Show, Eq, Generic)
+
+instance ToJSON TaskStats
+
+instance FromJSON TaskStats
+
+-- Get task statistics
+getTaskStats :: IO TaskStats
+getTaskStats = do
+  tasks <- loadTasks
+  ready <- getReadyTasks
+  let total = length tasks
+      open = length <| filter (\t -> taskStatus t == Open) tasks
+      inProg = length <| filter (\t -> taskStatus t == InProgress) tasks
+      done = length <| filter (\t -> taskStatus t == Done) tasks
+      epics = length <| filter (\t -> taskType t == Epic) tasks
+      readyCount = length ready
+      blockedCount = total - readyCount - done
+      -- Count tasks by priority
+      byPriority =
+        [ (P0, length <| filter (\t -> taskPriority t == P0) tasks),
+          (P1, length <| filter (\t -> taskPriority t == P1) tasks),
+          (P2, length <| filter (\t -> taskPriority t == P2) tasks),
+          (P3, length <| filter (\t -> taskPriority t == P3) tasks),
+          (P4, length <| filter (\t -> taskPriority t == P4) tasks)
+        ]
+      -- Count tasks by namespace
+      namespaces = mapMaybe taskNamespace tasks
+      uniqueNs = List.nub namespaces
+      byNamespace = map (\ns -> (ns, length <| filter (\t -> taskNamespace t == Just ns) tasks)) uniqueNs
+  pure
+    TaskStats
+      { totalTasks = total,
+        openTasks = open,
+        inProgressTasks = inProg,
+        doneTasks = done,
+        totalEpics = epics,
+        readyTasks = readyCount,
+        blockedTasks = blockedCount,
+        tasksByPriority = byPriority,
+        tasksByNamespace = byNamespace
+      }
+
+-- Show task statistics (human-readable)
+showTaskStats :: IO ()
+showTaskStats = do
+  stats <- getTaskStats
+  putText "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
+  putText "Task Statistics"
+  putText "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
+  putText <| "Total tasks:       " <> T.pack (show (totalTasks stats))
+  putText <| "  Open:            " <> T.pack (show (openTasks stats))
+  putText <| "  In Progress:     " <> T.pack (show (inProgressTasks stats))
+  putText <| "  Done:            " <> T.pack (show (doneTasks stats))
+  putText ""
+  putText <| "Epics:             " <> T.pack (show (totalEpics stats))
+  putText ""
+  putText <| "Ready to work:     " <> T.pack (show (readyTasks stats))
+  putText <| "Blocked:           " <> T.pack (show (blockedTasks stats))
+  putText ""
+  putText "By Priority:"
+  traverse_ printPriority (tasksByPriority stats)
+  unless (null (tasksByNamespace stats)) <| do
+    putText ""
+    putText "By Namespace:"
+    traverse_ printNamespace (tasksByNamespace stats)
+  putText "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
+  where
+    printPriority (p, count) =
+      let label = case p of
+            P0 -> "P0 (Critical)"
+            P1 -> "P1 (High)"
+            P2 -> "P2 (Medium)"
+            P3 -> "P3 (Low)"
+            P4 -> "P4 (Backlog)"
+       in putText <| "  " <> T.pack (show count) <> " " <> label
+    printNamespace (ns, count) =
+      putText <| "  " <> T.pack (show count) <> " " <> ns
+
 -- Import tasks: Read from another JSONL file and merge with existing tasks
 importTasks :: FilePath -> IO ()
 importTasks filePath = do