feat: improve opening trainer flow and add deviation dialog

- Add tutor message guardrail to prevent rapid-fire messages
  - Track last message by move index
  - Wait for both player and opponent moves before speaking
  - Speak immediately when player deviates from theory

- Add deviation dialog with three options:
  - Continue Playing (Start Game) - transitions to game mode
  - Undo & Return to Opening - returns to theory
  - Explore This Variation - continues off-book practice

- Implement smooth game mode transition:
  - Pass opening context from trainer to game
  - Tutor welcomes player with context about their study
  - Computer makes first move if needed in starting position

- Fix generate-test-fixtures script:
  - Add safety check to prevent overwriting real data
  - Restore full opening database (12,379 openings)
  - Rebuild move index (12,377 sequences)
  - Add clear warnings about test fixtures

- Update ChessGame to accept openingContext prop
- Update Tutor to display contextual greeting in game mode

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

scripts/generate-test-fixtures.ts

@@ -0,0 +1,138 @@
+#!/usr/bin/env tsx
+
+/**
+ * Generate Test Fixtures from Real Opening Data
+ *
+ * This script creates a subset of the opening database for e2e testing.
+ * It extracts a representative sample from each ECO file to keep tests fast
+ * while still using realistic data.
+ */
+
+import fs from 'fs';
+import path from 'path';
+
+const OPENINGS_DIR = path.join(__dirname, '../public/openings');
+const FIXTURES_DIR = path.join(__dirname, '../e2e/fixtures/openings');
+const ECO_FILES = ['ecoA.json', 'ecoB.json', 'ecoC.json', 'ecoD.json', 'ecoE.json'];
+
+// Number of openings to extract from each ECO file
+const SAMPLE_SIZE = 5;
+
+console.log('🔧 Generating test fixtures from real opening data...\n');
+
+// Safety check: Ensure we're not accidentally reading from test fixtures
+const sampleFile = path.join(OPENINGS_DIR, ECO_FILES[0]);
+const sampleData = JSON.parse(fs.readFileSync(sampleFile, 'utf8'));
+const entryCount = Object.keys(sampleData).length;
+
+if (entryCount < 100) {
+  console.error('❌ ERROR: Source opening files appear to be test fixtures (too few entries)!');
+  console.error(`   Found only ${entryCount} entries in ${ECO_FILES[0]}`);
+  console.error('   Expected hundreds of entries from the real database.');
+  console.error('\n💡 To restore the real opening data:');
+  console.error('   git checkout 30f1e9e -- public/openings/eco*.json');
+  console.error('   node scripts/buildOpeningIndex.js');
+  process.exit(1);
+}
+
+console.log(`✓ Verified source data integrity (${entryCount} openings in ${ECO_FILES[0]})\n`);
+
+// Ensure fixtures directory exists
+if (!fs.existsSync(FIXTURES_DIR)) {
+  fs.mkdirSync(FIXTURES_DIR, { recursive: true });
+}
+
+// Process each ECO file
+for (const filename of ECO_FILES) {
+  const sourcePath = path.join(OPENINGS_DIR, filename);
+  const targetPath = path.join(FIXTURES_DIR, filename);
+
+  console.log(`📖 Processing ${filename}...`);
+
+  try {
+    // Read the full ECO file
+    const data = JSON.parse(fs.readFileSync(sourcePath, 'utf8'));
+    const entries = Object.entries(data);
+
+    // Take a sample from the beginning
+    const sample: Record<string, any> = {};
+    const sampleEntries = entries.slice(0, SAMPLE_SIZE);
+
+    for (const [fen, opening] of sampleEntries) {
+      sample[fen] = opening;
+    }
+
+    // Write the fixture file
+    fs.writeFileSync(targetPath, JSON.stringify(sample, null, 2), 'utf8');
+    console.log(`   ✓ Created fixture with ${sampleEntries.length} openings`);
+  } catch (error) {
+    console.error(`   ✗ Error processing ${filename}:`, error instanceof Error ? error.message : error);
+    process.exit(1);
+  }
+}
+
+console.log('\n📊 Building move index for fixtures...');
+
+// Build move index from fixture files
+const allOpenings: any[] = [];
+
+for (const filename of ECO_FILES) {
+  const filepath = path.join(FIXTURES_DIR, filename);
+  const data = JSON.parse(fs.readFileSync(filepath, 'utf8'));
+  const entries = Object.entries(data);
+
+  for (const [fen, opening] of entries) {
+    allOpenings.push({
+      fen,
+      ...opening as any
+    });
+  }
+}
+
+// Build move sequence index
+const moveIndex: Record<string, any[]> = {};
+
+for (const opening of allOpenings) {
+  const moveSequence = opening.moves.trim();
+
+  if (!moveIndex[moveSequence]) {
+    moveIndex[moveSequence] = [];
+  }
+
+  // Remove the 'fen' field to reduce file size
+  const { fen, ...openingData } = opening;
+  moveIndex[moveSequence].push(openingData);
+}
+
+// Sort each array of openings
+for (const moveSequence in moveIndex) {
+  moveIndex[moveSequence].sort((a, b) => {
+    const aLength = a.moves.length;
+    const bLength = b.moves.length;
+
+    if (aLength !== bLength) {
+      return aLength - bLength;
+    }
+
+    return a.name.localeCompare(b.name);
+  });
+}
+
+// Write move index
+const moveIndexPath = path.join(FIXTURES_DIR, 'moveIndex.json');
+fs.writeFileSync(moveIndexPath, JSON.stringify(moveIndex, null, 2), 'utf8');
+console.log(`   ✓ Created move index with ${Object.keys(moveIndex).length} sequences`);
+
+console.log('\n✅ Test fixtures generated successfully!\n');
+console.log('📁 Fixture files created in:');
+console.log(`   ${FIXTURES_DIR}/\n`);
+console.log('📋 Files:');
+console.log('   • ecoA.json (5 sample openings)');
+console.log('   • ecoB.json (5 sample openings)');
+console.log('   • ecoC.json (5 sample openings)');
+console.log('   • ecoD.json (5 sample openings)');
+console.log('   • ecoE.json (5 sample openings)');
+console.log('   • moveIndex.json (generated index)');
+console.log('\n⚠️  WARNING: These are TEST FIXTURES ONLY!');
+console.log('   Do NOT copy these to public/openings/ - they will overwrite real data!');
+console.log('   The e2e tests should read from e2e/fixtures/openings/ directory.');