fix: indent docstring body in help paste output

Command name stays flush-left, docstring lines indented 4 spaces.
Plugin descriptions in the full reference also indented under headers.
Adds test_help_paste_body_indented to verify formatting.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_core.py

@@ -130,10 +130,19 @@ def _cmd_no_doc():
     pass
 
 
-def _make_fp_module(url="https://paste.example.com/abc/raw"):
-    """Create a fake flaskpaste module that returns a fixed URL."""
+def _make_fp_module(url="https://paste.example.com/abc/raw", capture=None):
+    """Create a fake flaskpaste module that returns a fixed URL.
+
+    If capture is a list, appended paste content is stored there.
+    """
     mod = types.ModuleType("flaskpaste")
-    mod.create_paste = lambda bot, text: url
+
+    def _create(bot, text):
+        if capture is not None:
+            capture.append(text)
+        return url
+
+    mod.create_paste = _create
     return mod
 
 
@@ -227,3 +236,23 @@ class TestHelpCommand:
         assert len(bot.replied) == 1
         assert "!widget -- Manage widgets" in bot.replied[0]
         assert "https://" not in bot.replied[0]
+
+    def test_help_paste_body_indented(self):
+        """Paste body has command name flush-left, docstring indented."""
+        bot = _FakeBot()
+        pastes: list[str] = []
+        bot.registry._modules["flaskpaste"] = _make_fp_module(capture=pastes)
+        bot.registry.commands["widget"] = _FakeHandler(
+            name="widget", callback=_cmd_with_doc,
+            help="Manage widgets", plugin="widgets",
+        )
+        msg = _Msg(text="!help widget")
+        asyncio.run(_mod.cmd_help(bot, msg))
+        assert len(pastes) == 1
+        lines = pastes[0].split("\n")
+        # First line: command header, no indent
+        assert lines[0] == "!widget -- Manage widgets"
+        # Docstring lines are indented 4 spaces
+        for line in lines[1:]:
+            if line.strip():
+                assert line.startswith("    "), f"not indented: {line!r}"