fix(tui): resolve lint and AmbiguousStep errors in TuiMaterializer

- Fix ruff format violations: collapse list comprehension in
  materializer.py, collapse function signature, collapse decorators
  and assertion in tui_materializer_steps.py, remove trailing
  whitespace in vulture_whitelist.py
- Remove duplicate Behave step definitions from tui_materializer_steps.py
  that conflicted with output_rendering_steps.py and
  project_commands_coverage_steps.py: create status handle,
  create code handle, close panel handle, close status handle,
  no error should be raised
- Rename render_element_for_tui step texts to avoid conflict with
  tui_first_run_steps.py: rendered text should contain/be empty ->
  render output should contain/be empty
- Update tui_materializer.feature to use renamed step texts and
  replace no error should be raised with materializer still running

ISSUES CLOSED: #11164

features/tui_materializer.feature

@@ -31,7 +31,7 @@ Feature: TUI Materializer
   Scenario: TuiMaterializer implements on_session_begin
     When I create a TuiMaterializer without a callback
     And I call on_session_begin with a mock session
-    Then no error should be raised
+    Then the materializer should still be running
 
   Scenario: TuiMaterializer emits element_created event for panel
     When I create a TuiMaterializer without a callback
@@ -141,72 +141,72 @@ Feature: TUI Materializer
 
   Scenario: render_element_for_tui renders Panel with title and entries
     When I render a Panel element with title "Info" and entry "key" "value"
-    Then the rendered text should contain "Info"
-    And the rendered text should contain "key"
-    And the rendered text should contain "value"
+    Then the render output should contain "Info"
+    And the render output should contain "key"
+    And the render output should contain "value"
 
   Scenario: render_element_for_tui renders Table with columns and rows
     When I render a Table element with title "Data" and column "Name"
-    Then the rendered text should contain "Data"
-    And the rendered text should contain "Name"
+    Then the render output should contain "Data"
+    And the render output should contain "Name"
 
   Scenario: render_element_for_tui renders StatusMessage ok level
     When I render a StatusMessage element with level "ok" and message "Success"
-    Then the rendered text should contain "ok"
-    And the rendered text should contain "Success"
+    Then the render output should contain "ok"
+    And the render output should contain "Success"
 
   Scenario: render_element_for_tui renders StatusMessage error level
     When I render a StatusMessage element with level "error" and message "Failed"
-    Then the rendered text should contain "error"
-    And the rendered text should contain "Failed"
+    Then the render output should contain "error"
+    And the render output should contain "Failed"
 
   Scenario: render_element_for_tui renders indeterminate ProgressIndicator
     When I render an indeterminate ProgressIndicator with label "Thinking"
-    Then the rendered text should contain "Thinking"
+    Then the render output should contain "Thinking"
 
   Scenario: render_element_for_tui renders determinate ProgressIndicator
     When I render a determinate ProgressIndicator with label "Loading" current 5 total 10
-    Then the rendered text should contain "Loading"
-    And the rendered text should contain "50%"
+    Then the render output should contain "Loading"
+    And the render output should contain "50%"
 
   Scenario: render_element_for_tui renders Tree with root and children
     When I render a Tree element with root "root" and child "child1"
-    Then the rendered text should contain "root"
-    And the rendered text should contain "child1"
+    Then the render output should contain "root"
+    And the render output should contain "child1"
 
   Scenario: render_element_for_tui renders CodeBlock with language
     When I render a CodeBlock element with language "python" and content "x = 1"
-    Then the rendered text should contain "python"
-    And the rendered text should contain "x = 1"
+    Then the render output should contain "python"
+    And the render output should contain "x = 1"
 
   Scenario: render_element_for_tui renders DiffBlock with hunks
     When I render a DiffBlock element with file_a "old.py" and file_b "new.py"
-    Then the rendered text should contain "old.py"
-    And the rendered text should contain "new.py"
+    Then the render output should contain "old.py"
+    And the render output should contain "new.py"
 
   Scenario: render_element_for_tui renders Separator line style
     When I render a Separator element with style "line"
-    Then the rendered text should contain "-"
+    Then the render output should contain "-"
 
   Scenario: render_element_for_tui renders Separator blank style
     When I render a Separator element with style "blank"
-    Then the rendered text should be empty
+    Then the render output should be empty
 
   Scenario: render_element_for_tui renders Separator double style
     When I render a Separator element with style "double"
-    Then the rendered text should contain "="
+    Then the render output should contain "="
 
   Scenario: render_element_for_tui renders ActionHint with commands
     When I render an ActionHint element with command "agents plan list"
-    Then the rendered text should contain "agents plan list"
+    Then the render output should contain "agents plan list"
 
   Scenario: render_element_for_tui renders TextBlock content
     When I render a TextBlock element with content "Hello world"
-    Then the rendered text should contain "Hello world"
+    Then the render output should contain "Hello world"
 
   Scenario: render_element_for_tui renders TextBlock with indent
     When I render a TextBlock element with content "indented" and indent 4
-    Then the rendered text should contain "    indented"
+    Then the render output should contain "    indented"
 
   # ── A2A event routing ─────────────────────────────────────────────────────