feat(auth): add admin bootstrap and username login

Initialize admin bootstrap settings during startup, persist username support in auth flows, and align frontend auth requests with local API behavior.

backend/app/database.py

@@ -3,6 +3,7 @@ from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sess
 from sqlalchemy.orm import DeclarativeBase
 from app.config import settings
 import os
+import re
 
 os.makedirs(settings.DATA_DIR, exist_ok=True)
 
@@ -37,6 +38,8 @@ async def init_db():
         await ensure_log_columns(conn)
         await ensure_message_columns(conn)
         await ensure_document_columns(conn)
+        await ensure_user_columns(conn)
+        await ensure_forum_columns(conn)
 
 
 async def ensure_log_columns(conn):
@@ -93,3 +96,93 @@ async def ensure_document_columns(conn):
     for column, ddl in required_columns.items():
         if column not in columns:
             await conn.execute(text(ddl))
+
+
+async def ensure_user_columns(conn):
+    rows = await _get_table_info(conn, 'users')
+    if not rows:
+        return
+
+    columns = {row[1] for row in rows}
+    if 'username' not in columns:
+        await conn.execute(text("ALTER TABLE users ADD COLUMN username VARCHAR(255)"))
+        rows = await _get_table_info(conn, 'users')
+
+    await _backfill_usernames(conn)
+
+    username_row = next(row for row in rows if row[1] == 'username')
+    indexes = await _get_index_info(conn, 'users')
+    has_username_index = any(row[1] == 'ix_users_username' and row[2] == 1 for row in indexes)
+    has_email_index = any(row[1] == 'ix_users_email' and row[2] == 1 for row in indexes)
+
+    if username_row[3] != 1 or not has_username_index or not has_email_index:
+        await _rebuild_users_table(conn)
+
+
+async def ensure_forum_columns(conn):
+    rows = await _get_table_info(conn, 'forum_posts')
+    if not rows:
+        return
+
+    columns = {row[1] for row in rows}
+    required_columns = {
+        "board": "ALTER TABLE forum_posts ADD COLUMN board VARCHAR(100) DEFAULT 'general' NOT NULL",
+        "is_pinned": "ALTER TABLE forum_posts ADD COLUMN is_pinned BOOLEAN DEFAULT 0 NOT NULL",
+    }
+    for column, ddl in required_columns.items():
+        if column not in columns:
+            await conn.execute(text(ddl))
+
+    indexes = await _get_index_info(conn, 'forum_posts')
+    index_names = {row[1] for row in indexes}
+    if 'ix_forum_posts_board' not in index_names:
+        await conn.execute(text("CREATE INDEX IF NOT EXISTS ix_forum_posts_board ON forum_posts (board)"))
+
+
+async def _backfill_usernames(conn):
+    result = await conn.execute(text("SELECT id, email, username FROM users ORDER BY created_at, id"))
+    users = result.fetchall()
+    seen_usernames: set[str] = set()
+
+    for user_id, email, username in users:
+        if username:
+            seen_usernames.add(username)
+            continue
+
+        base_username = _slugify_username((email or '').split('@', 1)[0])
+        candidate = base_username
+        suffix = 2
+        while candidate in seen_usernames:
+            candidate = f"{base_username}_{suffix}"
+            suffix += 1
+
+        await conn.execute(
+            text("UPDATE users SET username = :username WHERE id = :user_id AND username IS NULL"),
+            {"username": candidate, "user_id": user_id},
+        )
+        seen_usernames.add(candidate)
+
+
+async def _rebuild_users_table(conn):
+    await conn.execute(text("CREATE TABLE users__new (id VARCHAR(36) PRIMARY KEY, username VARCHAR(255) NOT NULL, email VARCHAR(255) NOT NULL, hashed_password VARCHAR(255) NOT NULL, full_name VARCHAR(255), is_active BOOLEAN NOT NULL DEFAULT 1, is_superuser BOOLEAN NOT NULL DEFAULT 0, llm_config JSON, scheduler_config JSON, created_at DATETIME NOT NULL, updated_at DATETIME NOT NULL)"))
+    await conn.execute(text("INSERT INTO users__new (id, username, email, hashed_password, full_name, is_active, is_superuser, llm_config, scheduler_config, created_at, updated_at) SELECT id, username, email, hashed_password, full_name, COALESCE(is_active, 1), COALESCE(is_superuser, 0), llm_config, scheduler_config, COALESCE(created_at, CURRENT_TIMESTAMP), COALESCE(updated_at, CURRENT_TIMESTAMP) FROM users"))
+    await conn.execute(text("DROP TABLE users"))
+    await conn.execute(text("ALTER TABLE users__new RENAME TO users"))
+    await conn.execute(text("CREATE UNIQUE INDEX IF NOT EXISTS ix_users_username ON users (username)"))
+    await conn.execute(text("CREATE UNIQUE INDEX IF NOT EXISTS ix_users_email ON users (email)"))
+
+
+async def _get_table_info(conn, table_name: str):
+    result = await conn.execute(text(f"PRAGMA table_info({table_name})"))
+    return result.fetchall()
+
+
+async def _get_index_info(conn, table_name: str):
+    result = await conn.execute(text(f"PRAGMA index_list({table_name})"))
+    return result.fetchall()
+
+
+def _slugify_username(value: str) -> str:
+    normalized = re.sub(r'[^a-z0-9_]+', '_', value.strip().lower())
+    normalized = re.sub(r'_+', '_', normalized).strip('_')
+    return normalized or 'user'