feat(gui): sidebar sections + non-technical tool labels

Sidebar nav now groups tools under Data Review / Data Cleaners /
Transformations / Automations via st.navigation, replacing the flat
auto-discovered list. Tool display names switch to action-first
phrasing (Find Duplicates, Fix Missing Values, Find Unusual Values,
Standardize Formats, Clean Text, Quality Check, Map Columns, Combine
Files, Automated Workflows) in EN + ES packs and on each page's H1.

The Data Cleaners section follows the requested order: Missing
Values → Outliers → Text Cleaner → Format Standardizer → Deduplicator
→ Quality Check. (Text Cleaner kept inside cleaners since the request
didn't list it but the tool still ships.) Registry now carries a
section field; helpers added: tools_in_section(), section_label().

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/gui/pages/1_Deduplicator.py

@@ -54,7 +54,7 @@ for key, default in _DEFAULTS.items():
 # Header
 # ---------------------------------------------------------------------------
 
-st.title("🔍 Deduplicator")
+st.title("🔍 Find Duplicates")
 st.caption("Find and remove duplicate rows in CSV, delimited text, and Excel files.")
 
 
@@ -363,5 +363,5 @@ else:
 st.divider()
 st.caption(
     "Runs locally. Your data never leaves this computer. "
-    "| DataTools Deduplicator v3.0"
+    "| DataTools v3.0"
 )

src/gui/pages/2_Text_Cleaner.py

@@ -39,7 +39,7 @@ require_normalization_gate()
 # Header
 # ---------------------------------------------------------------------------
 
-st.title("✂️ Text Cleaner")
+st.title("✂️ Clean Text")
 st.caption(
     "Trim whitespace, fold smart quotes, strip invisible characters, and "
     "normalize line endings. Runs locally — your data never leaves this computer."

src/gui/pages/3_Format_Standardizer.py

@@ -37,7 +37,7 @@ require_normalization_gate()
 # Header
 # ---------------------------------------------------------------------------
 
-st.title("📐 Format Standardizer")
+st.title("📐 Standardize Formats")
 st.caption(
     "Canonicalize dates, phone numbers, currency, names, addresses, and "
     "booleans on a per-column basis. Runs locally — your data never leaves "

src/gui/pages/4_Missing_Values.py

@@ -38,7 +38,7 @@ require_normalization_gate()
 # Header
 # ---------------------------------------------------------------------------
 
-st.title("🕳️ Missing Value Handler")
+st.title("🕳️ Fix Missing Values")
 st.caption(
     "Detect disguised nulls, profile missingness, and apply imputation or "
     "drop strategies. Runs locally — your data never leaves this computer."

src/gui/pages/5_Column_Mapper.py

@@ -39,7 +39,7 @@ require_normalization_gate()
 # Header
 # ---------------------------------------------------------------------------
 
-st.title("🗂️ Column Mapper")
+st.title("🗂️ Map Columns")
 st.caption(
     "Rename columns, enforce a target schema, and coerce types. Runs locally — "
     "your data never leaves this computer."

src/gui/pages/6_Outlier_Detector.py

@@ -26,7 +26,7 @@ require_normalization_gate()
 # Header
 # ---------------------------------------------------------------------------
 
-st.title("📊 Outlier Detector")
+st.title("📊 Find Unusual Values")
 st.caption("Detect and handle outliers in numeric columns.")
 
 st.info("This tool is under development.")

src/gui/pages/7_Multi_File_Merger.py

@@ -26,7 +26,7 @@ require_normalization_gate()
 # Header
 # ---------------------------------------------------------------------------
 
-st.title("📎 Multi-File Merger")
+st.title("📎 Combine Files")
 st.caption("Combine multiple CSV and Excel files into one dataset.")
 
 st.info("This tool is under development.")

src/gui/pages/8_Validator_Reporter.py

@@ -26,7 +26,7 @@ require_normalization_gate()
 # Header
 # ---------------------------------------------------------------------------
 
-st.title("✅ Validator & Reporter")
+st.title("✅ Quality Check")
 st.caption("Validate data against rules and generate quality reports.")
 
 st.info("This tool is under development.")

src/gui/pages/9_Pipeline_Runner.py

@@ -40,7 +40,7 @@ require_normalization_gate()
 # Header
 # ---------------------------------------------------------------------------
 
-st.title("⚙️ Pipeline Runner")
+st.title("⚙️ Automated Workflows")
 st.caption(
     "Chain DataTools cleaning steps into one repeatable workflow. The "
     "pipeline recommends an order; you stay in control."