feat: hide Streamlit chrome for app-like appearance

Add shared hide_streamlit_chrome() helper that removes header bar,
hamburger menu, footer, and deploy button via CSS injection. Called
on every page. Add .streamlit/config.toml with minimal toolbar mode.

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

src/gui/pages/1_Deduplicator.py

@@ -19,10 +19,12 @@ from src.core.io import read_file, list_sheets, detect_encoding, detect_delimite
 from src.gui.components import (
     apply_review_decisions,
     config_panel,
+    hide_streamlit_chrome,
     match_group_card,
     results_summary,
 )
 
+hide_streamlit_chrome()
 
 # ---------------------------------------------------------------------------
 # Session state defaults

src/gui/pages/2_Text_Cleaner.py

@@ -11,6 +11,10 @@ _project_root = Path(__file__).resolve().parent.parent.parent.parent
 if str(_project_root) not in sys.path:
     sys.path.insert(0, str(_project_root))
 
+from src.gui.components import hide_streamlit_chrome
+
+hide_streamlit_chrome()
+
 # ---------------------------------------------------------------------------
 # Header
 # ---------------------------------------------------------------------------

src/gui/pages/3_Format_Standardizer.py

@@ -11,6 +11,10 @@ _project_root = Path(__file__).resolve().parent.parent.parent.parent
 if str(_project_root) not in sys.path:
     sys.path.insert(0, str(_project_root))
 
+from src.gui.components import hide_streamlit_chrome
+
+hide_streamlit_chrome()
+
 # ---------------------------------------------------------------------------
 # Header
 # ---------------------------------------------------------------------------

src/gui/pages/4_Missing_Values.py

@@ -11,6 +11,10 @@ _project_root = Path(__file__).resolve().parent.parent.parent.parent
 if str(_project_root) not in sys.path:
     sys.path.insert(0, str(_project_root))
 
+from src.gui.components import hide_streamlit_chrome
+
+hide_streamlit_chrome()
+
 # ---------------------------------------------------------------------------
 # Header
 # ---------------------------------------------------------------------------

src/gui/pages/5_Column_Mapper.py

@@ -11,6 +11,10 @@ _project_root = Path(__file__).resolve().parent.parent.parent.parent
 if str(_project_root) not in sys.path:
     sys.path.insert(0, str(_project_root))
 
+from src.gui.components import hide_streamlit_chrome
+
+hide_streamlit_chrome()
+
 # ---------------------------------------------------------------------------
 # Header
 # ---------------------------------------------------------------------------

src/gui/pages/6_Outlier_Detector.py

@@ -11,6 +11,10 @@ _project_root = Path(__file__).resolve().parent.parent.parent.parent
 if str(_project_root) not in sys.path:
     sys.path.insert(0, str(_project_root))
 
+from src.gui.components import hide_streamlit_chrome
+
+hide_streamlit_chrome()
+
 # ---------------------------------------------------------------------------
 # Header
 # ---------------------------------------------------------------------------

src/gui/pages/7_Multi_File_Merger.py

@@ -11,6 +11,10 @@ _project_root = Path(__file__).resolve().parent.parent.parent.parent
 if str(_project_root) not in sys.path:
     sys.path.insert(0, str(_project_root))
 
+from src.gui.components import hide_streamlit_chrome
+
+hide_streamlit_chrome()
+
 # ---------------------------------------------------------------------------
 # Header
 # ---------------------------------------------------------------------------

src/gui/pages/8_Validator_Reporter.py

@@ -11,6 +11,10 @@ _project_root = Path(__file__).resolve().parent.parent.parent.parent
 if str(_project_root) not in sys.path:
     sys.path.insert(0, str(_project_root))
 
+from src.gui.components import hide_streamlit_chrome
+
+hide_streamlit_chrome()
+
 # ---------------------------------------------------------------------------
 # Header
 # ---------------------------------------------------------------------------

src/gui/pages/9_Pipeline_Runner.py

@@ -11,6 +11,10 @@ _project_root = Path(__file__).resolve().parent.parent.parent.parent
 if str(_project_root) not in sys.path:
     sys.path.insert(0, str(_project_root))
 
+from src.gui.components import hide_streamlit_chrome
+
+hide_streamlit_chrome()
+
 # ---------------------------------------------------------------------------
 # Header
 # ---------------------------------------------------------------------------