Pane(feat[capture_pane]): add alternate-screen, quiet, and escape-markup flags

why: capture-pane supports flags for alternate screen capture, silent error
handling, and markup escaping that were not exposed.
what:
- Add alternate_screen (-a), quiet (-q), escape_markup (-M, 3.6+) parameters
- Version-gate escape_markup with has_gte_version("3.6")
- Add tests for quiet, alternate_screen, and escape_markup flags

Author: tony

src/libtmux/pane.py

@@ -326,6 +326,9 @@ def capture_pane(
         join_wrapped: bool = False,
         preserve_trailing: bool = False,
         trim_trailing: bool = False,
+        alternate_screen: bool = False,
+        quiet: bool = False,
+        escape_markup: bool = False,
     ) -> list[str]:
         r"""Capture text from pane.
 
@@ -371,6 +374,17 @@ def capture_pane(
             Requires tmux 3.4+. If used with tmux < 3.4, a warning
             is issued and the flag is ignored.
             Default: False
+        alternate_screen : bool, optional
+            Capture from the alternate screen (``-a`` flag).
+            Default: False
+        quiet : bool, optional
+            Suppress errors silently (``-q`` flag).
+            Default: False
+        escape_markup : bool, optional
+            Escape markup in the output (``-M`` flag). Requires tmux 3.6+.
+            Default: False
+
+            .. versionadded:: 0.45
 
         Returns
         -------
@@ -418,6 +432,18 @@ def capture_pane(
                     "trim_trailing requires tmux 3.4+, ignoring",
                     stacklevel=2,
                 )
+        if alternate_screen:
+            cmd.append("-a")
+        if quiet:
+            cmd.append("-q")
+        if escape_markup:
+            if has_gte_version("3.6", tmux_bin=self.server.tmux_bin):
+                cmd.append("-M")
+            else:
+                warnings.warn(
+                    "escape_markup requires tmux 3.6+, ignoring",
+                    stacklevel=2,
+                )
         return self.cmd(*cmd).stdout
 
     def send_keys(

tests/test_pane_capture_pane.py

@@ -470,3 +470,37 @@ def prompt_ready() -> bool:
         # Check warning was issued
         assert len(w) == 1
         assert "trim_trailing requires tmux 3.4+" in str(w[0].message)
+
+
+def test_capture_pane_quiet(session: Session) -> None:
+    """Test capture_pane with quiet flag suppresses errors."""
+    pane = session.active_window.active_pane
+    assert pane is not None
+
+    # Quiet mode should not raise, even in edge cases
+    result = pane.capture_pane(quiet=True)
+    assert isinstance(result, list)
+
+
+def test_capture_pane_alternate_screen(session: Session) -> None:
+    """Test capture_pane with alternate_screen flag."""
+    pane = session.active_window.active_pane
+    assert pane is not None
+
+    # Capture from alternate screen — may be empty, but should not error
+    result = pane.capture_pane(alternate_screen=True)
+    assert isinstance(result, list)
+
+
+def test_capture_pane_escape_markup(session: Session) -> None:
+    """Test capture_pane with escape_markup flag (3.6+)."""
+    from libtmux.common import has_gte_version
+
+    if not has_gte_version("3.6"):
+        pytest.skip("Requires tmux 3.6+")
+
+    pane = session.active_window.active_pane
+    assert pane is not None
+
+    result = pane.capture_pane(escape_markup=True)
+    assert isinstance(result, list)