refactor: tech debt reduction - extract hooks, deduplicate helpers, update deps, add CI

- Extract useCustomStepFlow hook from TreeNavigationPage (1040 → 759 lines)
- Create core/filters.py with shared tree/step visibility filters
- Create services/export_service.py from session export logic
- Add GitHub Actions CI/CD pipeline (pytest + lint + build)
- Add GIN index migration for full-text search on trees
- Update FastAPI 0.128.5, Pydantic 2.12.5, SQLAlchemy 2.0.46, +5 more
- Fix regex → pattern deprecation in Query() params

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

backend/app/services/export_service.py

@@ -0,0 +1,162 @@
+"""
+Session export generators for ResolutionFlow.
+
+Provides markdown, plain text, and HTML export formatters
+for troubleshooting sessions.
+"""
+import html
+
+from app.models.session import Session
+from app.schemas.session import SessionExport
+
+
+def generate_markdown_export(session: Session, options: SessionExport) -> str:
+    """Generate markdown export."""
+    lines = []
+
+    if options.include_tree_info:
+        tree_name = session.tree_snapshot.get("name", "Troubleshooting Session")
+        lines.append(f"# {tree_name}")
+        lines.append("")
+        if session.ticket_number:
+            lines.append(f"**Ticket:** {session.ticket_number}")
+        if session.client_name:
+            lines.append(f"**Client:** {session.client_name}")
+        if options.include_timestamps:
+            lines.append(f"**Started:** {session.started_at.strftime('%Y-%m-%d %H:%M')}")
+            if session.completed_at:
+                lines.append(f"**Completed:** {session.completed_at.strftime('%Y-%m-%d %H:%M')}")
+        lines.append("")
+        lines.append("---")
+        lines.append("")
+
+    # Scratchpad / Evidence section
+    scratchpad = getattr(session, 'scratchpad', '') or ''
+    if scratchpad.strip():
+        lines.append("## Evidence / Reference")
+        lines.append("")
+        lines.append(scratchpad)
+        lines.append("")
+        lines.append("---")
+        lines.append("")
+
+    lines.append("## Troubleshooting Steps")
+    lines.append("")
+
+    for i, decision in enumerate(session.decisions, 1):
+        question = decision.get("question") or decision.get("action_performed", "Step")
+        answer = decision.get("answer", "")
+        notes = decision.get("notes", "")
+
+        lines.append(f"### Step {i}: {question}")
+        if answer:
+            lines.append(f"**Answer:** {answer}")
+        if notes:
+            lines.append(f"**Notes:** {notes}")
+        if options.include_timestamps and decision.get("timestamp"):
+            lines.append(f"*{decision['timestamp']}*")
+        lines.append("")
+
+    return "\n".join(lines)
+
+
+def generate_text_export(session: Session, options: SessionExport) -> str:
+    """Generate plain text export."""
+    lines = []
+
+    if options.include_tree_info:
+        tree_name = session.tree_snapshot.get("name", "Troubleshooting Session")
+        lines.append(tree_name)
+        lines.append("=" * len(tree_name))
+        if session.ticket_number:
+            lines.append(f"Ticket: {session.ticket_number}")
+        if session.client_name:
+            lines.append(f"Client: {session.client_name}")
+        if options.include_timestamps:
+            lines.append(f"Started: {session.started_at.strftime('%Y-%m-%d %H:%M')}")
+            if session.completed_at:
+                lines.append(f"Completed: {session.completed_at.strftime('%Y-%m-%d %H:%M')}")
+        lines.append("")
+
+    # Scratchpad / Evidence section
+    scratchpad = getattr(session, 'scratchpad', '') or ''
+    if scratchpad.strip():
+        lines.append("EVIDENCE / REFERENCE")
+        lines.append("-" * 20)
+        lines.append(scratchpad)
+        lines.append("")
+
+    lines.append("TROUBLESHOOTING STEPS")
+    lines.append("-" * 20)
+
+    for i, decision in enumerate(session.decisions, 1):
+        question = decision.get("question") or decision.get("action_performed", "Step")
+        answer = decision.get("answer", "")
+        notes = decision.get("notes", "")
+
+        lines.append(f"\n{i}. {question}")
+        if answer:
+            lines.append(f"   Answer: {answer}")
+        if notes:
+            lines.append(f"   Notes: {notes}")
+
+    return "\n".join(lines)
+
+
+def generate_html_export(session: Session, options: SessionExport) -> str:
+    """Generate HTML export."""
+    tree_name = html.escape(session.tree_snapshot.get("name", "Troubleshooting Session"))
+
+    html_parts = ['<!DOCTYPE html>', '<html>', '<head>',
+            '<meta charset="UTF-8">',
+            f'<title>{tree_name}</title>',
+            '<style>',
+            'body { font-family: Arial, sans-serif; max-width: 800px; margin: 0 auto; padding: 20px; }',
+            'h1 { color: #333; }',
+            '.meta { color: #666; margin-bottom: 20px; }',
+            '.step { margin-bottom: 15px; padding: 10px; background: #f5f5f5; border-radius: 5px; }',
+            '.step h3 { margin: 0 0 10px 0; color: #444; }',
+            '.answer { font-weight: bold; }',
+            '.notes { font-style: italic; color: #555; }',
+            '.timestamp { font-size: 0.85em; color: #888; }',
+            '</style>',
+            '</head>', '<body>']
+
+    if options.include_tree_info:
+        html_parts.append(f'<h1>{tree_name}</h1>')
+        html_parts.append('<div class="meta">')
+        if session.ticket_number:
+            html_parts.append(f'<p><strong>Ticket:</strong> {html.escape(session.ticket_number)}</p>')
+        if session.client_name:
+            html_parts.append(f'<p><strong>Client:</strong> {html.escape(session.client_name)}</p>')
+        if options.include_timestamps:
+            html_parts.append(f'<p><strong>Started:</strong> {session.started_at.strftime("%Y-%m-%d %H:%M")}</p>')
+            if session.completed_at:
+                html_parts.append(f'<p><strong>Completed:</strong> {session.completed_at.strftime("%Y-%m-%d %H:%M")}</p>')
+        html_parts.append('</div>')
+
+    # Scratchpad / Evidence section
+    scratchpad = getattr(session, 'scratchpad', '') or ''
+    if scratchpad.strip():
+        html_parts.append('<h2>Evidence / Reference</h2>')
+        html_parts.append(f'<div class="scratchpad" style="white-space: pre-wrap; background: #f9f9f9; padding: 12px; border-radius: 4px; margin-bottom: 20px;">{html.escape(scratchpad)}</div>')
+
+    html_parts.append('<h2>Troubleshooting Steps</h2>')
+
+    for i, decision in enumerate(session.decisions, 1):
+        question = html.escape(decision.get("question") or decision.get("action_performed", "Step"))
+        answer = html.escape(decision.get("answer", ""))
+        notes = html.escape(decision.get("notes", ""))
+
+        html_parts.append('<div class="step">')
+        html_parts.append(f'<h3>Step {i}: {question}</h3>')
+        if answer:
+            html_parts.append(f'<p class="answer">Answer: {answer}</p>')
+        if notes:
+            html_parts.append(f'<p class="notes">Notes: {notes}</p>')
+        if options.include_timestamps and decision.get("timestamp"):
+            html_parts.append(f'<p class="timestamp">{html.escape(str(decision["timestamp"]))}</p>')
+        html_parts.append('</div>')
+
+    html_parts.extend(['</body>', '</html>'])
+    return "\n".join(html_parts)