rebuild(stage-10): deliver mentor and unified llm streaming

next/backend/database/migrations/m0008_mentor_llm.py

@@ -0,0 +1,93 @@
+from __future__ import annotations
+
+import sqlite3
+
+from backend.database.migrations.runner import Migration
+
+
+def upgrade(connection: sqlite3.Connection) -> None:
+    statements = (
+        """
+        CREATE TABLE mentor_preferences (
+            user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+            mentor_id TEXT NOT NULL,
+            pinned INTEGER NOT NULL DEFAULT 0 CHECK (pinned IN (0, 1)),
+            sort_order INTEGER NOT NULL DEFAULT 0,
+            updated_at TEXT NOT NULL,
+            PRIMARY KEY (user_id, mentor_id)
+        )
+        """,
+        """
+        CREATE TABLE llm_requests (
+            id TEXT PRIMARY KEY,
+            user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+            feature TEXT NOT NULL,
+            business_id TEXT NOT NULL,
+            prompt_version TEXT NOT NULL,
+            status TEXT NOT NULL CHECK (
+                status IN ('reserved', 'streaming', 'success', 'failed', 'stopped')
+            ),
+            started_at TEXT NOT NULL,
+            completed_at TEXT,
+            duration_ms INTEGER NOT NULL DEFAULT 0,
+            error_type TEXT NOT NULL DEFAULT '',
+            input_chars INTEGER NOT NULL DEFAULT 0,
+            output_chars INTEGER NOT NULL DEFAULT 0
+        )
+        """,
+        "CREATE INDEX llm_requests_user_started_idx ON llm_requests(user_id, started_at)",
+        """
+        CREATE TABLE llm_attempts (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            request_id TEXT NOT NULL REFERENCES llm_requests(id) ON DELETE CASCADE,
+            model_id INTEGER REFERENCES llm_models(id) ON DELETE SET NULL,
+            role TEXT NOT NULL CHECK (role IN ('primary', 'fallback')),
+            status TEXT NOT NULL CHECK (status IN ('streaming', 'success', 'failed', 'stopped')),
+            started_at TEXT NOT NULL,
+            completed_at TEXT,
+            duration_ms INTEGER NOT NULL DEFAULT 0,
+            error_type TEXT NOT NULL DEFAULT '',
+            input_chars INTEGER NOT NULL DEFAULT 0,
+            output_chars INTEGER NOT NULL DEFAULT 0
+        )
+        """,
+        "CREATE INDEX llm_attempts_request_idx ON llm_attempts(request_id, id)",
+        """
+        CREATE TABLE mentor_messages (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+            mentor_id TEXT NOT NULL,
+            trade_date TEXT NOT NULL,
+            role TEXT NOT NULL CHECK (role IN ('user', 'assistant')),
+            content TEXT NOT NULL,
+            request_id TEXT REFERENCES llm_requests(id) ON DELETE SET NULL,
+            status TEXT NOT NULL CHECK (status IN ('complete', 'stopped', 'error')),
+            created_at TEXT NOT NULL
+        )
+        """,
+        """
+        CREATE INDEX mentor_messages_scope_idx
+        ON mentor_messages(user_id, mentor_id, trade_date, id)
+        """,
+    )
+    for statement in statements:
+        connection.execute(statement)
+
+
+def downgrade(connection: sqlite3.Connection) -> None:
+    for table in (
+        "mentor_messages",
+        "llm_attempts",
+        "llm_requests",
+        "mentor_preferences",
+    ):
+        connection.execute(f"DROP TABLE {table}")
+
+
+MIGRATION = Migration(
+    version=8,
+    name="create_mentor_and_llm_audit",
+    signature="mentor-llm:v1:preferences-messages-requests-attempts",
+    upgrade=upgrade,
+    downgrade=downgrade,
+)