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

userbot/modules/hearts.py

@@ -37,20 +37,20 @@ async def _wrap_edit(message: Message, text: str):
 
 async def phase1(message: Message):
     """Big scroll"""
-    BIG_SCROLL = '🧡💛💚💙💜🖤🤎'
+    big_scroll = '🧡💛💚💙💜🖤🤎'
     await _wrap_edit(message, joined_heart)
-    for heart in BIG_SCROLL:
+    for heart in big_scroll:
         await _wrap_edit(message, joined_heart.replace(R, heart))
         await asyncio.sleep(SLEEP)
 
 
 async def phase2(message: Message):
     """Per-heart randomiser"""
-    ALL = ['❤️'] + list('🧡💛💚💙💜🤎🖤')  # don't include white heart
+    all_hearts = ['❤️'] + list('🧡💛💚💙💜🤎🖤')  # don't include white heart
 
     format_heart = joined_heart.replace(R, '{}')
     for _ in range(5):
-        heart = format_heart.format(*random.choices(ALL, k=heartlet_len))  # noqa: S311
+        heart = format_heart.format(*random.choices(all_hearts, k=heartlet_len))  # noqa: S311
         await _wrap_edit(message, heart)
         await asyncio.sleep(SLEEP)
 
@@ -75,7 +75,7 @@ async def phase4(message: Message):
 
 
 @Client.on_message(filters.command('hearts', prefix) & filters.me)
-async def hearts(client: Client, message: Message):
+async def hearts(_client: Client, message: Message):
     await phase1(message)
     await phase2(message)
     await phase3(message)