Enhanced Textual TUI with proper API usage and documentation

- Fixed DataTable row selection and event handling
- Added explicit column keys to prevent auto-generated keys
- Implemented row-to-flow mapping for reliable selection tracking
- Converted left metrics panel to horizontal top bar
- Fixed all missing FlowStats/EnhancedAnalysisData attributes
- Created comprehensive Textual API documentation in Documentation/textual/
- Added validation checklist to prevent future API mismatches
- Preserved cursor position during data refreshes
- Fixed RowKey type handling and event names

The TUI now properly handles flow selection, displays metrics in a compact top bar,
and correctly correlates selected rows with the details pane.

WIDE_GRID_IMPROVEMENTS.md

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+# Wide Grid Layout Improvements
+
+## Enhanced Column Specifications
+
+The grid view has been significantly widened to ensure proper column alignment and readability:
+
+### Column Width Changes
+
+| Column | Old Width | New Width | Alignment | Description |
+|--------|-----------|-----------|-----------|-------------|
+| # | 2 chars | 3 chars | Right | Flow number |
+| Source | 20 chars | 24 chars | Left | IP:port source endpoint |
+| Proto | 6 chars | 8 chars | Left | Transport protocol (UDP, TCP, etc.) |
+| Destination | 20 chars | 24 chars | Left | IP:port destination endpoint |
+| Extended | 10 chars | 12 chars | Left | Extended protocol (CH10, PTP, etc.) |
+| Frame Type | 12 chars | 15 chars | Left | Specific frame type |
+| Pkts | 6 chars | 8 chars | Right | Packet count |
+| Volume | 8 chars | 10 chars | Right | Data volume with units |
+| Timing | 8 chars | 10 chars | Right | Inter-arrival timing |
+| Quality | 8 chars | 10 chars | Right | Quality percentage/status |
+
+### Total Width Calculation
+
+- **Previous total**: ~93 characters
+- **New total**: ~124 characters 
+- **Width increase**: ~33% wider for better readability
+
+## Alignment Improvements
+
+### Source and Destination Fields
+- Increased from 20 to 24 characters
+- Supports longer IP addresses and port numbers
+- Truncation threshold increased from 18 to 22 characters
+- Better accommodation for IPv4 addresses with high port numbers
+
+### Right-Aligned Numeric Columns
+- All numeric columns now have 2 extra characters of width
+- Ensures proper right-edge alignment for:
+  - Packet counts (up to 99,999,999)
+  - Volume with units (up to 999.9MB)
+  - Timing values (up to 99.9s)
+  - Quality percentages (up to 100.0%)
+
+### Visual Hierarchy
+- Sub-rows now use 4-character indent to match wider flow number column
+- Perfect alignment maintained between main flows and sub-rows
+- All columns line up precisely regardless of data content
+
+## Layout Example
+
+```
+  #   Source                   Proto    Destination              Extended     Frame Type        Pkts    Volume      Timing     Quality
+  1   192.168.4.89:1024       UDP      239.1.2.10:8080         3 types      Mixed             1452      1.9MB      77.8ms     Enhanced
+                                                                CH10         CH10-Data         1110     1.44MB       102ms       76.4%
+                                                                CH10         TMATS              114      148KB       990ms        7.8%
+                                                                             UDP                228      296KB       493ms       15.7%
+```
+
+## Technical Changes
+
+### Formatting Functions Updated
+1. **`_format_flow_summary_line()`**: Updated to use new column widths
+2. **`_format_protocol_frame_line()`**: Updated to match main flow alignment
+3. **Header formatting**: Expanded to accommodate wider columns
+4. **Truncation logic**: Removed `[:width-8]` constraints that were cutting off data
+
+### IP Address Handling
+- Source/Destination truncation increased from 10 to 14 characters before ellipsis
+- Better support for longer IP addresses and port combinations
+- Maintains readability while showing more endpoint information
+
+## Benefits
+
+1. **Perfect Column Alignment**: All numeric columns now line up properly on their right edges
+2. **No Data Truncation**: Removed width constraints that were cutting off information
+3. **Better Readability**: Increased spacing makes complex flow data easier to scan
+4. **Professional Appearance**: Wider grid looks more polished and organized
+5. **Future-Proof**: Accommodates longer protocol names and extended data
+
+The wide grid layout ensures that complex telemetry flow analysis is presented in a clear, professional format that makes the hierarchical protocol breakdown easy to understand at a glance.