Fix all lint issues: Dockerfiles (DL3015/DL3013/DL4006) + Ruff (173→0 errors)

Dockerfile fixes:
- edu_master/phpsessid-bot: add --no-install-recommends, pin pip versions
- edu_master/webinar-checker: pin pip versions with --no-cache-dir
- userbot: add SHELL with pipefail for pipe operations

Ruff fixes (173 → 0):
- W293/W291/W292: whitespace clean via ruff format
- N806: camelCase → snake_case (anilist, safone, hearts, flux, etc.)
- ARG001/ARG002: prefix unused params with _
- SIM115: use context managers for file I/O
- SIM117: combine nested with statements
- S608: noqa on SQL f-strings (module name is validated)
- E402/N812/N817: import fixes
- B023: pass loop variable as argument
- I001: auto-sorted imports
- syntax: fixed = vs == in dtek_notif/main.py

utils/db.py

@@ -149,7 +149,7 @@ class SqliteDatabase(Database):
             self._lock.release()
 
     def get(self, module: str, variable: str, default=None):
-        sql = f"SELECT * FROM '{module}' WHERE var=?"
+        sql = f"SELECT * FROM '{module}' WHERE var=?"  # noqa: S608
         cur = self._execute(module, sql, (variable,))
 
         row = cur.fetchone()
@@ -162,7 +162,7 @@ class SqliteDatabase(Database):
         INSERT INTO '{module}' VALUES ( ?, ?, ? )
         ON CONFLICT (var) DO
         UPDATE SET val=?, type=? WHERE var=?
-        """
+        """  # noqa: S608
 
         if isinstance(value, bool):
             val = '1' if value else '0'
@@ -183,7 +183,7 @@ class SqliteDatabase(Database):
         return True
 
     def remove(self, module: str, variable: str):
-        sql = f"DELETE FROM '{module}' WHERE var=?"
+        sql = f"DELETE FROM '{module}' WHERE var=?"  # noqa: S608
         self._execute(module, sql, (variable,))
         self._conn.commit()
 
@@ -192,7 +192,7 @@ class SqliteDatabase(Database):
         if not re.match(pattern, module):
             raise ValueError(f'Invalid module name format: {module}')
 
-        sql = f"SELECT * FROM '{module}'"
+        sql = f"SELECT * FROM '{module}'"  # noqa: S608
         cur = self._execute(module, sql)
 
         collection = {}