Add the task log: recent tasks with status, Enter shows the log

l on the main screen opens "Tasks", the recent cluster tasks newest
first. l on the info screen shows only that guest's tasks. Columns:
start, duration (or "running"), node, type, VMID ("-" for node
tasks), user and status. A failed task gets a "!" in the leading
column. Enter opens the task's log in a plain-text widget, so the
output is never parsed as markup.

`task list -o json` has no start or end times, so the list comes from
`/cluster/tasks`. The upid is validated (it must start with "UPID:")
before it goes in as a positional argument.

Review fixes:
- A finished task without a start time no longer crashes the app; its
  duration shows "-".
- "running" now means there is no endtime. A finished task with an
  empty status shows "unknown" and is flagged.

Read-only live check: 25 tasks listed, and the log of the newest
(vzdelsnapshot 104) ends with TASK OK.

Closes #10

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/cv4pve_tui/app.py

@@ -18,6 +18,7 @@ from textual.widgets import (
     Header,
     Input,
     Label,
+    Log,
     OptionList,
     Select,
     Static,
@@ -417,6 +418,124 @@ class NetScreen(DialogScreen):
         )
 
 
+class TaskLogScreen(DialogScreen):
+    """The log of one task, as plain text (task output is never parsed as markup)."""
+
+    BINDINGS = [("escape", "dismiss", "Close")]  # noqa: RUF012 - Textual idiom
+    DEFAULT_CSS = """
+    TaskLogScreen #dialog { width: 120; height: 90%; }
+    TaskLogScreen Log { height: 1fr; }
+    """
+
+    def __init__(self, entry: dict) -> None:
+        super().__init__()
+        self.entry = entry
+
+    def compose(self) -> ComposeResult:
+        t = self.entry
+        with self.box(f"Log: {t.get('type', '')} {t.get('id') or t.get('node', '')}"):
+            yield Log(id="tasklog")
+
+    def on_mount(self) -> None:
+        self._load_worker()
+
+    @work(thread=True)
+    def _load_worker(self) -> None:
+        try:
+            text = cli.task_log(self.entry["upid"])
+        except Exception as exc:  # noqa: BLE001 - surface every failure, never kill the app
+            self.app.call_from_thread(self.app.notify, _message(exc), severity="error")
+            return
+        self.app.call_from_thread(self.query_one("#tasklog", Log).write, text)
+
+
+def _duration(task: dict) -> str:
+    end, start = task.get("endtime"), task.get("starttime")
+    if not end:
+        return "running"
+    if not start:
+        return "-"  # finished, but the start is unknown
+    secs = max(0, int(end - start))
+    if secs >= 3600:
+        return f"{secs // 3600}h {secs % 3600 // 60}m"
+    return f"{secs // 60}m {secs % 60}s" if secs >= 60 else f"{secs}s"
+
+
+class TasksScreen(ModalScreen):
+    """Recent cluster tasks, or those of one guest (vmid); Enter shows a task's log."""
+
+    BINDINGS = [  # noqa: RUF012 - Textual idiom
+        ("escape", "dismiss", "Close"),
+        ("g", "reload", "Refresh"),
+    ]
+    DEFAULT_CSS = """
+    TasksScreen { align: center middle; }
+    TasksScreen #tasks_section {
+        width: 100%; height: 100%; border: round $accent; border-title-style: bold;
+        padding: 0 1; background: $surface;
+    }
+    TasksScreen DataTable { height: 1fr; }
+    """
+
+    def __init__(self, guest: dict | None = None) -> None:
+        super().__init__()
+        self.guest = guest
+
+    def compose(self) -> ComposeResult:
+        title = "Tasks"
+        if self.guest:
+            title += f": {self.guest['name']} ({self.guest['vmid']})"
+        with Vertical(id="tasks_section") as section:
+            section.border_title = Text(title)  # guest names: never markup
+            yield DataTable(id="tasks", cursor_type="row")
+            yield Static("", id="tasks_note", markup=False)
+        yield Footer()
+
+    def on_mount(self) -> None:
+        self.rows: list[dict] = []
+        self.query_one("#tasks", DataTable).add_columns(
+            "", "Start", "Duration", "Node", "Type", "VMID", "User", "Status"
+        )
+        self.action_reload()
+
+    def action_reload(self) -> None:
+        self._load_worker()
+
+    @work(thread=True)
+    def _load_worker(self) -> None:
+        try:
+            tasks = cli.tasks()
+        except Exception as exc:  # noqa: BLE001 - surface every failure, never kill the app
+            self.app.call_from_thread(self.app.notify, _message(exc), severity="error")
+            return
+        if self.guest:
+            tasks = [t for t in tasks if t.get("id") == str(self.guest["vmid"])]
+        self.app.call_from_thread(self._fill, tasks)
+
+    def _fill(self, tasks: list[dict]) -> None:
+        self.rows = tasks
+        table = self.query_one("#tasks", DataTable)
+        table.clear()
+        for t in tasks:
+            # running = no endtime yet; a finished task without a status text is "unknown"
+            status = "running" if not t.get("endtime") else t.get("status") or "unknown"
+            _add_plain(
+                table,
+                "!" if status not in ("OK", "running") else "",
+                _when(t.get("starttime")),
+                _duration(t),
+                t.get("node", ""),
+                t.get("type", ""),
+                t.get("id") or "-",
+                t.get("user", ""),
+                status,
+            )
+        self.query_one("#tasks_note", Static).update("" if tasks else "No tasks")
+
+    def on_data_table_row_selected(self, event: DataTable.RowSelected) -> None:
+        self.app.push_screen(TaskLogScreen(self.rows[event.cursor_row]))
+
+
 class InfoScreen(ModalScreen):
     """Backups, backup job and network of one guest (read-only), plus backup now."""
 
@@ -431,6 +550,7 @@ class InfoScreen(ModalScreen):
         ("p", "snapshot", "Take snapshot"),
         ("R", "rollback", "Roll back"),
         ("D", "delete_snapshot", "Delete snapshot"),
+        ("l", "tasks", "Tasks"),
     ]
     DEFAULT_CSS = """
     InfoScreen DataTable { height: auto; max-height: 12; }
@@ -501,6 +621,9 @@ class InfoScreen(ModalScreen):
     def action_reload(self) -> None:
         self._load_worker()
 
+    def action_tasks(self) -> None:
+        self.app.push_screen(TasksScreen(self.guest))
+
     @work(thread=True)
     def _load_worker(self) -> None:
         self.load()
@@ -808,6 +931,7 @@ class GuestApp(App):
         ("t", "shell", "Shell"),
         ("g", "reload", "Refresh"),
         ("c", "context", "Context"),
+        ("l", "tasks", "Tasks"),
         ("q", "quit", "Quit"),
     ]
 
@@ -856,6 +980,9 @@ class GuestApp(App):
         self._show_context()
         self.action_reload()
 
+    def action_tasks(self) -> None:
+        self.push_screen(TasksScreen())
+
     def _show_context_frame(self, sub_title: str) -> None:
         self.context_name = sub_title.removeprefix("context: ")
         self._update_frame()