Fix Gameday lineup row selection and deselect behavior

- Fix bug where clicking to select a player in the middle of the lineup
  would operate on the last added player instead of the clicked row
- Deselect now requires clicking the same row twice (for screenshots)
- Clicking the table after deselect re-enables selection mode
- Fix main.py to actually launch the TUI app
- Add CLAUDE.md with codebase documentation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,90 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+SBA Scout is a TUI (Terminal User Interface) application for SBA fantasy baseball scouting and team management. Built with Textual for the interface, SQLAlchemy for async database operations, and pydantic-settings for configuration.
+
+## Commands
+
+```bash
+# Install dependencies (use uv, not pip)
+uv pip install -e .
+
+# Run the application
+sba-scout          # via console script
+python main.py     # direct execution
+
+# Lint code
+ruff check src/
+ruff check --fix src/   # auto-fix
+
+# Format code
+ruff format src/
+```
+
+There is no test suite currently (tests/ directory exists but is empty).
+
+## Architecture
+
+### Layer Structure
+
+```
+src/sba_scout/
+├── api/           # External API integration
+├── calc/          # Scoring and statistics calculations
+├── db/            # SQLAlchemy models and queries
+├── screens/       # Textual UI screens
+├── app.py         # Main application and DashboardScreen
+└── config.py      # Pydantic settings management
+```
+
+### Data Flow
+
+1. **API Layer** (`api/`) syncs data from League API → SQLite database
+2. **CSV Import** (`api/importer.py`) loads batter/pitcher card data from spreadsheets
+3. **Database Layer** (`db/`) stores teams, players, cards, lineups
+4. **Calc Layer** (`calc/`) computes standardized matchup scores using league stats
+5. **UI Layer** (`screens/`, `app.py`) displays data via Textual TUI
+
+### Key Patterns
+
+- **Async throughout**: SQLAlchemy async with aiosqlite, httpx async client
+- **Lazy singletons**: `get_settings()` returns global Settings, database engine initialized on first use
+- **Context managers**: API client and database sessions use `async with`
+- **Layered config**: Pydantic defaults → .env file → data/settings.yaml (user editable)
+
+### Database Models (db/models.py)
+
+Core models: `Team`, `Player`, `BatterCard`, `PitcherCard`, `Lineup`, `MatchupCache`, `StandardizedScoreCache`, `SyncStatus`, `Transaction`
+
+### Screens (screens/)
+
+- `roster.py` - Tabbed roster view (majors/minors/IL)
+- `matchup.py` - Batter vs pitcher analysis
+- `lineup.py` - Lineup builder with drag/drop
+- `gameday.py` - Combined matchup + lineup view
+- `settings.py` - Configuration UI with YAML persistence
+
+### Matchup Scoring System (calc/)
+
+- Standardizes stats to -3 to +3 range based on league averages/stdev
+- Handedness-aware (vLHP/vRHP for batters, vLHB/vRHB for pitchers)
+- Weighted composite scores with tier assignment (A/B/C/D/F)
+- Cached for performance in `StandardizedScoreCache`
+
+## Configuration
+
+Environment variables use `SBA_SCOUT_` prefix with `__` for nesting:
+- `SBA_SCOUT_API__BASE_URL`
+- `SBA_SCOUT_API__API_KEY`
+- `SBA_SCOUT_TEAM__TEAM_ABBREV`
+
+User settings saved to `data/settings.yaml` (editable via Settings screen or directly).
+
+## Code Style
+
+- Line length: 100 characters
+- Python 3.12+
+- Ruff rules: E, F, I, N, W, UP (standard + imports + naming + upgrades)

main.py

@@ -1,6 +1,4 @@
-def main():
-    print("Hello from sba-scout!")
-
+from sba_scout.app import main
 
 if __name__ == "__main__":
     main()

src/sba_scout/screens/gameday.py

@@ -12,9 +12,10 @@ import logging
 from dataclasses import dataclass
 from typing import ClassVar, Optional
 
-from textual.app import ComposeResult
+from textual.app import ComposeResult, on
 from textual.binding import Binding
 from textual.containers import Horizontal, ScrollableContainer, Vertical
+from textual.events import Click
 from textual.screen import Screen
 from textual.widgets import (
     Button,
@@ -91,6 +92,7 @@ class GamedayScreen(Screen):
     lineup_slots: list[LineupSlot] = []
     saved_lineups: list[Lineup] = []
     current_lineup_name: str = ""
+    _last_lineup_row: int | None = None  # Track last selected row for deselect toggle
 
     def compose(self) -> ComposeResult:
         """Compose the gameday layout with side-by-side panels."""
@@ -465,15 +467,17 @@ class GamedayScreen(Screen):
             await self.action_save_lineup()
 
     def on_data_table_row_selected(self, event: DataTable.RowSelected) -> None:
-        """Handle row selection - toggle cursor off if clicking same row."""
+        """Handle row selection - toggle cursor off only if clicking same row twice."""
         table = event.data_table
         if table.id == "lineup-table":
-            # If cursor is "row" type, switch to "none" to hide highlight
-            # User can click again or use arrow keys to restore
-            if table.cursor_type == "row":
+            current_row = event.cursor_row
+            # Only toggle off if clicking the same row that was already selected
+            if table.cursor_type == "row" and current_row == self._last_lineup_row:
                 table.cursor_type = "none"
+                self._last_lineup_row = None
             else:
                 table.cursor_type = "row"
+                self._last_lineup_row = current_row
 
     def on_data_table_row_highlighted(self, event: DataTable.RowHighlighted) -> None:
         """Re-enable cursor when navigating with keys."""
@@ -482,6 +486,14 @@ class GamedayScreen(Screen):
             # Re-enable cursor when user navigates
             table.cursor_type = "row"
 
+    @on(Click, "#lineup-table")
+    def on_lineup_table_click(self, event: Click) -> None:
+        """Re-enable cursor when lineup table is clicked while deselected."""
+        lineup_table = self.query_one("#lineup-table", DataTable)
+        if lineup_table.cursor_type == "none":
+            lineup_table.cursor_type = "row"
+            self._last_lineup_row = None
+
     # =========================================================================
     # Actions
     # =========================================================================