build: 打通 FastAPI 与 Vue 最小工程、依赖与数据库连接

后端入口、配置、Redis 与 Alembic 迁移就位；前端 Vite 工程可安装可构建。

backend/alembic/versions/chat_channel_status_001.py

@@ -0,0 +1,64 @@
+"""Track channel delivery receipts on chat_history
+
+WhatsApp reports sent / delivered / read / failed for every message we send,
+keyed by its platform message id (wamid). Storing that id on the row is what
+lets a receipt find its message; channel_status holds the latest receipt.
+
+channel_status is deliberately separate from attributes.delivery_status: the
+inbox reads any delivery_status as "not delivered", so a 'read' written there
+would show as a failure.
+
+Revision ID: chat_channel_status_001
+Revises: idx_kq_org_status_001
+Create Date: 2026-10-11
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+# Keep revision ids under 32 characters: alembic_version.version_num is
+# varchar(32).
+revision: str = 'chat_channel_status_001'
+down_revision: Union[str, None] = 'idx_kq_org_status_001'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+INDEX_NAME = 'ix_chat_history_org_external_message'
+
+
+def upgrade() -> None:
+    # if_not_exists throughout: the columns commit before the index builds
+    # (CONCURRENTLY can't share their transaction), so a start that dies
+    # mid-build must be able to run this again.
+    op.add_column('chat_history', sa.Column('external_message_id', sa.String(), nullable=True),
+                  if_not_exists=True)
+    op.add_column('chat_history', sa.Column('channel_status', sa.String(16), nullable=True),
+                  if_not_exists=True)
+    op.add_column('chat_history', sa.Column('channel_status_at', sa.TIMESTAMP(timezone=True),
+                                            nullable=True),
+                  if_not_exists=True)
+    # Partial: only channel messages carry an id, so widget rows stay out of it.
+    # Built CONCURRENTLY so a large chat_history keeps taking writes while it
+    # builds — migrations run on backend start. That can't run in a
+    # transaction, hence the autocommit block. A build that fails part-way
+    # leaves an INVALID index that IF NOT EXISTS would then skip: if that
+    # happens, DROP INDEX ix_chat_history_org_external_message and restart.
+    with op.get_context().autocommit_block():
+        op.create_index(
+            INDEX_NAME, 'chat_history', ['organization_id', 'external_message_id'],
+            unique=False,
+            postgresql_where=sa.text('external_message_id IS NOT NULL'),
+            postgresql_concurrently=True,
+            if_not_exists=True,
+        )
+
+
+def downgrade() -> None:
+    with op.get_context().autocommit_block():
+        op.drop_index(INDEX_NAME, table_name='chat_history',
+                      postgresql_concurrently=True, if_exists=True)
+    op.drop_column('chat_history', 'channel_status_at', if_exists=True)
+    op.drop_column('chat_history', 'channel_status', if_exists=True)
+    op.drop_column('chat_history', 'external_message_id', if_exists=True)