feat: add Answer Question feature

.gitattributes

@@ -0,0 +1 @@
+backend/start.sh text eol=lf

backend/alembic/versions/6e2d1d2b7c4a_add_ai_interactions.py

@@ -0,0 +1,54 @@
+"""Add ai_interactions table
+
+Revision ID: 6e2d1d2b7c4a
+Revises: af24fc97a432
+Create Date: 2026-03-20 15:50:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = '6e2d1d2b7c4a'
+down_revision: Union[str, Sequence[str], None] = 'af24fc97a432'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Create Enum types
+    # Note: Using sa.Enum in create_table will automatically create the type if it doesn't exist,
+    # but for PostgreSQL it's often better to create it explicitly if we want to be safe.
+
+    op.create_table('ai_interactions',
+    sa.Column('id', sa.UUID(), nullable=False),
+    sa.Column('user_id', sa.UUID(), nullable=False),
+    sa.Column('document_id', sa.UUID(), nullable=False),
+    sa.Column('interaction_type', sa.Enum('highlight', 'question', 'summary', 'quiz', name='aiinteractiontype'), nullable=False),
+    sa.Column('action', sa.Enum('explain_simple', 'define', 'analogy', 'example', 'expand_acronym', 'answer_question', name='aiactiontype'), nullable=False),
+    sa.Column('input_text', sa.Text(), nullable=False),
+    sa.Column('response_text', sa.Text(), nullable=False),
+    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
+    sa.ForeignKeyConstraint(['document_id'], ['documents.id'], ondelete='CASCADE'),
+    sa.ForeignKeyConstraint(['user_id'], ['users.id'], ondelete='CASCADE'),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('id')
+    )
+    op.create_index(op.f('ix_ai_interactions_document_id'), 'ai_interactions', ['document_id'], unique=False)
+    op.create_index(op.f('ix_ai_interactions_user_id'), 'ai_interactions', ['user_id'], unique=False)
+    op.create_index('idx_user_document', 'ai_interactions', ['user_id', 'document_id'], unique=False)
+
+
+def downgrade() -> None:
+    op.drop_index('idx_user_document', table_name='ai_interactions')
+    op.drop_index(op.f('ix_ai_interactions_user_id'), table_name='ai_interactions')
+    op.drop_index(op.f('ix_ai_interactions_document_id'), table_name='ai_interactions')
+    op.drop_table('ai_interactions')
+
+    # Drop types
+    # Note: Be careful with dropping types if they are used elsewhere, but here they are specific to this table.
+    sa.Enum(name='aiinteractiontype').drop(op.get_bind())
+    sa.Enum(name='aiactiontype').drop(op.get_bind())

backend/app/models/ai_interaction.py

@@ -21,6 +21,7 @@ class AIActionType(enum.Enum):
   analogy = "analogy"
   example = "example"
   expand_acronym = "expand_acronym"
+  answer_question = "answer_question"
 
 
 class AIInteraction(Base):

backend/app/prompts/highlight/answer_question.md

@@ -0,0 +1,12 @@
+DOCUMENT CONTEXT:
+{{context}}
+
+QUESTION:
+{{selected_text}}
+
+TASK:
+Answer the selected question based on the document context provided.
+If the context doesn't contain the answer, state that clearly instead of guessing.
+Strict Constraint: Provide the answer immediately. Do not say "Sure", "Here is the answer", or "Based on the text". Start with the core answer.
+
+ANSWER:

backend/requirements.txt

@@ -51,7 +51,7 @@ pydantic_core==2.41.5
 Pygments==2.19.2
 pyiceberg==0.10.0
 PyJWT==2.11.0
-PyMuPDF==1.26.7
+pymupdf>=1.26.0
 pyparsing==3.3.2
 pypdf==6.7.0
 pyroaring==1.0.3

docker-compose.dev.yml

@@ -0,0 +1,24 @@
+services:
+  backend:
+    build:
+      context: ./backend
+      dockerfile: Dockerfile
+    env_file:
+      - ./backend/.env.dev
+    volumes:
+      - ./backend:/app
+      - /app/.venv
+      - /app/__pycache__
+
+  frontend:
+    build:
+      context: ./frontend
+      dockerfile: Dockerfile
+      args:
+        - VITE_MODE=dev
+    env_file:
+      - ./frontend/.env.dev
+    volumes:
+      - ./frontend:/app
+      - /app/node_modules
+      - /app/dist

frontend/Dockerfile

@@ -12,8 +12,12 @@ RUN npm install
 # Copy source code
 COPY . .
 
+# Build arguments
+ARG VITE_MODE=production
+ENV VITE_MODE=$VITE_MODE
+
 # Build the application
-RUN npm run build
+RUN npm run build -- --mode $VITE_MODE
 
 # Stage 2: Serve the application with Nginx
 FROM nginx:alpine

frontend/src/components/study-room/constants.ts

@@ -1,11 +1,12 @@
-import { BookOpen, TextQuote, Lightbulb, MessageSquare, Hash } from 'lucide-react';
+import { BookOpen, TextQuote, Lightbulb, MessageSquare, Hash, HelpCircle } from 'lucide-react';
 
 export const aiActions = [
   { key: 'explain', label: 'Explain Simple', icon: BookOpen },
   { key: 'define', label: 'Define', icon: TextQuote },
   { key: 'example', label: 'Give Example', icon: Lightbulb },
   { key: 'analogy', label: 'Analogy', icon: MessageSquare },
   { key: 'acronym', label: 'Extend Acronym', icon: Hash },
+  { key: 'question', label: 'Answer Question', icon: HelpCircle },
 ] as const;
 
 export type ActionKey = (typeof aiActions)[number]['key'];

frontend/src/services/ai.service.ts

@@ -9,6 +9,7 @@ const ACTION_MAP: Record<string, string> = {
   example: 'example',
   analogy: 'analogy',
   acronym: 'expand_acronym',
+  question: 'answer_question',
 };
 
 /**