feat(bot): support concurrent drafts and reply-based edits with error resilience

ai procurement/app/models.py

@@ -41,7 +41,11 @@ class BotDraft(Base):
     """A prepared-but-not-committed ERP action (quote / supplier / material)."""
 
     __tablename__ = "bot_drafts"
-    __table_args__ = (Index("ix_bot_drafts_chat_status", "chat_id", "status"),)
+    __table_args__ = (
+        Index("ix_bot_drafts_chat_status", "chat_id", "status"),
+        Index("ix_bot_drafts_review_msg", "review_message_id"),
+        Index("ix_bot_drafts_source_msg", "source_message_id"),
+    )
 
     id: Mapped[str] = _uuid_pk()
     chat_id: Mapped[int] = mapped_column(BigInteger, nullable=False, index=True)
@@ -50,6 +54,7 @@ class BotDraft(Base):
     missing: Mapped[dict | None] = mapped_column(JSONB)
     status: Mapped[str] = mapped_column(String(16), nullable=False, default="active")  # active|committed|cancelled|expired|failed
     source: Mapped[str | None] = mapped_column(String(16))  # text|voice
+    source_message_id: Mapped[int | None] = mapped_column(BigInteger)
     review_message_id: Mapped[int | None] = mapped_column(BigInteger)
     last_bale_update_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
     created_at: Mapped[datetime] = _timestamptz()