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/demotivator.py

@@ -15,7 +15,9 @@ from PIL import Image, ImageDraw, ImageFont  # noqa: E402
 @Client.on_message(filters.command(['dem'], prefix) & filters.me)
 async def demotivator(client: Client, message: Message):
     await message.edit('<code>Process of demotivation...</code>', parse_mode=enums.ParseMode.HTML)
-    font = requests.get('https://github.com/The-MoonTg-project/files/blob/main/Times%20New%20Roman.ttf?raw=true', timeout=10)
+    font = requests.get(
+        'https://github.com/The-MoonTg-project/files/blob/main/Times%20New%20Roman.ttf?raw=true', timeout=10
+    )
     f = font.content
     template_dem = requests.get('https://raw.githubusercontent.com/files/main/demotivator.png', timeout=10)
     if message.reply_to_message: