Phase 4: Documents & Memory — upload, FTS, AI tools, context injection

Backend:
- Document + MemoryEntry models with Alembic migration (GIN FTS index)
- File upload endpoint with path traversal protection (sanitized filenames)
- Background document text extraction (PyMuPDF)
- Full-text search on extracted_text via PostgreSQL tsvector/tsquery
- Memory CRUD with enum-validated categories/importance, field allow-list
- AI tools: save_memory, search_documents, get_memory (Claude function calling)
- Tool execution loop in stream_ai_response (multi-turn tool use)
- Context assembly: injects critical memory + relevant doc excerpts
- File storage abstraction (local filesystem, S3-swappable)
- Secure file deletion (DB flush before disk delete)

Frontend:
- Document upload dialog (drag-and-drop + file picker)
- Document list with status badges, search, download (via authenticated blob)
- Document viewer with extracted text preview
- Memory list grouped by category with importance color coding
- Memory editor with category/importance dropdowns
- Documents + Memory pages with full CRUD
- Enabled sidebar navigation for both sections

Review fixes applied:
- Sanitized upload filenames (path traversal prevention)
- Download via axios blob (not bare <a href>, preserves auth)
- Route ordering: /search before /{id}/reindex
- Memory update allows is_active=False + field allow-list
- MemoryEditor form resets on mode switch
- Literal enum validation on category/importance schemas
- DB flush before file deletion for data integrity

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/alembic/versions/004_create_documents_and_memory_entries.py

@@ -0,0 +1,58 @@
+"""Create documents and memory_entries tables
+
+Revision ID: 004
+Revises: 003
+Create Date: 2026-03-19
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import UUID, JSONB
+
+revision: str = "004"
+down_revision: Union[str, None] = "003"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "documents",
+        sa.Column("id", UUID(as_uuid=True), primary_key=True, server_default=sa.text("gen_random_uuid()")),
+        sa.Column("user_id", UUID(as_uuid=True), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True),
+        sa.Column("filename", sa.String(255), nullable=False),
+        sa.Column("original_filename", sa.String(255), nullable=False),
+        sa.Column("storage_path", sa.Text, nullable=False),
+        sa.Column("mime_type", sa.String(100), nullable=False),
+        sa.Column("file_size", sa.BigInteger, nullable=False),
+        sa.Column("doc_type", sa.String(50), nullable=False, server_default="other"),
+        sa.Column("extracted_text", sa.Text, nullable=True),
+        sa.Column("processing_status", sa.String(20), nullable=False, server_default="pending"),
+        sa.Column("metadata", JSONB, nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+    )
+
+    op.execute(
+        "CREATE INDEX ix_documents_fts ON documents USING gin(to_tsvector('english', coalesce(extracted_text, '')))"
+    )
+
+    op.create_table(
+        "memory_entries",
+        sa.Column("id", UUID(as_uuid=True), primary_key=True, server_default=sa.text("gen_random_uuid()")),
+        sa.Column("user_id", UUID(as_uuid=True), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True),
+        sa.Column("category", sa.String(50), nullable=False),
+        sa.Column("title", sa.String(255), nullable=False),
+        sa.Column("content", sa.Text, nullable=False),
+        sa.Column("source_document_id", UUID(as_uuid=True), sa.ForeignKey("documents.id", ondelete="SET NULL"), nullable=True),
+        sa.Column("importance", sa.String(20), nullable=False, server_default="medium"),
+        sa.Column("is_active", sa.Boolean, nullable=False, server_default=sa.text("true")),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("memory_entries")
+    op.execute("DROP INDEX IF EXISTS ix_documents_fts")
+    op.drop_table("documents")