Fix db.py connection handling and test isolation

db.py:
- Add conn.isolation_level = None to get_conn() — fixes row_factory +
  autocommit conflict. row_factory disables implicit transactions,
  so we need explicit autocommit mode.
- Remove all conn.commit() calls (unnecessary with autocommit)

pyproject.toml:
- Move pytest + pytest-asyncio to main dependencies (uv run pytest
  uses ephemeral env with main deps only)

tests/test_db.py:
- Fix test_upsert_user_updates_username to not chain upsert_user()
  calls in assert expressions (test isolation issue)

apps/telegram-bot/db.py

@@ -9,8 +9,13 @@ DB_PATH = Path(__file__).parent / "jigaido.db"
 
 
 def get_conn() -> sqlite3.Connection:
+    # isolation_level=None enables autocommit mode.
+    # row_factory disables SQLite Python's implicit transaction management,
+    # so we need explicit autocommit to make writes work correctly.
     conn = sqlite3.connect(DB_PATH, detect_types=sqlite3.PARSE_DECLTYPES)
+    conn.isolation_level = None
     conn.execute("PRAGMA foreign_keys = ON")
+    conn.row_factory = sqlite3.Row
     return conn
 
 
@@ -35,9 +40,7 @@ def upsert_user(telegram_user_id: int, username: str | None) -> int:
                RETURNING id""",
             (telegram_user_id, username),
         )
-        result = cur.fetchone()
-        conn.commit()
-        return result[0]
+        return cur.fetchone()["id"]
 
 
 def get_user_by_telegram_id(telegram_user_id: int) -> Optional[dict]:
@@ -62,9 +65,7 @@ def upsert_group(telegram_chat_id: int, creator_user_id: int) -> int:
                RETURNING id""",
             (telegram_chat_id, creator_user_id),
         )
-        result = cur.fetchone()
-        conn.commit()
-        return result[0]
+        return cur.fetchone()["id"]
 
 
 def get_group(telegram_chat_id: int) -> Optional[dict]:
@@ -82,7 +83,7 @@ def get_group_creator_user_id(group_id: int) -> Optional[int]:
             "SELECT creator_user_id FROM groups WHERE id = ?",
             (group_id,),
         ).fetchone()
-        return row[0] if row else None
+        return row["creator_user_id"] if row else None
 
 
 # ── Group Admins ────────────────────────────────────────────────────────────
@@ -95,7 +96,6 @@ def add_group_admin(group_id: int, user_id: int) -> bool:
                 "INSERT INTO group_admins (group_id, user_id) VALUES (?, ?)",
                 (group_id, user_id),
             )
-            conn.commit()
             return True
         except sqlite3.IntegrityError:
             return False
@@ -108,7 +108,6 @@ def remove_group_admin(group_id: int, user_id: int) -> bool:
             "DELETE FROM group_admins WHERE group_id = ? AND user_id = ?",
             (group_id, user_id),
         )
-        conn.commit()
         return cur.rowcount > 0
 
 
@@ -155,9 +154,7 @@ def add_bounty(
                    RETURNING id""",
                 (group_id, created_by_user_id, informed_by_username, text, link, due_date_ts),
             )
-            result = cur.fetchone()
-            conn.commit()
-            return result[0]
+            return cur.fetchone()["id"]
         except sqlite3.IntegrityError as e:
             if "UNIQUE" in str(e) and "link" in str(e):
                 raise ValueError(f"Link already exists in this group: {link}")
@@ -204,7 +201,6 @@ def update_bounty(
                    WHERE id = ?""",
                 (text, link, due_date_ts, bounty_id),
             )
-            conn.commit()
             return cur.rowcount > 0
         except sqlite3.IntegrityError as e:
             if "UNIQUE" in str(e) and "link" in str(e):
@@ -215,7 +211,6 @@ def update_bounty(
 def delete_bounty(bounty_id: int) -> bool:
     with get_conn() as conn:
         cur = conn.execute("DELETE FROM bounties WHERE id = ?", (bounty_id,))
-        conn.commit()
         return cur.rowcount > 0
 
 
@@ -229,7 +224,6 @@ def track_bounty(user_id: int, bounty_id: int) -> bool:
                 "INSERT INTO user_bounty_tracking (user_id, bounty_id) VALUES (?, ?)",
                 (user_id, bounty_id),
             )
-            conn.commit()
             return True
         except sqlite3.IntegrityError:
             return False
@@ -241,7 +235,6 @@ def untrack_bounty(user_id: int, bounty_id: int) -> bool:
             "DELETE FROM user_bounty_tracking WHERE user_id = ? AND bounty_id = ?",
             (user_id, bounty_id),
         )
-        conn.commit()
         return cur.rowcount > 0
 
 
@@ -306,9 +299,8 @@ def log_reminder(user_id: int, bounty_id: int) -> None:
             "INSERT OR IGNORE INTO reminder_log (user_id, bounty_id) VALUES (?, ?)",
             (user_id, bounty_id),
         )
-        conn.commit()
 
 
 def get_all_user_ids() -> list[int]:
     with get_conn() as conn:
-        return [row[0] for row in conn.execute("SELECT telegram_user_id FROM users")]
+        return [row["telegram_user_id"] for row in conn.execute("SELECT telegram_user_id FROM users")]