fix: stop swallowing startup errors, fix fresh-install crashes on Windows

[MeloleM]

Closes #6.

What was wrong

Client.Save() ended with exit(0). Save() runs from close(), and discord.py calls close() in run()'s finally block, so SystemExit replaced whatever exception actually killed startup. Every failure — bad token, missing token, missing intents — produced the same silent output and exit code 0.

Changes

singletons.py — drop the exit(0) from Save(). close() now completes normally and the original exception propagates and prints. Shutdown still saves and still prints --- Client disconnected ---; the process just exits on its own instead of being killed mid-cleanup.

main.py — load_dotenv() behind a try/except ImportError, so a .env next to main.py works while python-dotenv stays optional and system environment variables keep priority. Missing econtoken now prints a readable message and exits 1 rather than reaching discord.py as None.

saveload/saveload.py — LoadUserDict() called os.mknod(), which doesn't exist on Windows, then pickle.load()'d the empty file it had just made. A missing or empty save file is now treated as an empty user_dict; SaveUserDict() creates the file on the first save.

README.md — added the Privileged Gateway Intents step (all three are required by Intents.all()), documented the .env option, and added python-dotenv to the install line.

Verification

Before, with no token set:

[INFO    ] discord.client: logging in using static token
. . . Saved Userdata Successfully !
--- Client disconnected ---

After, with no token set:

[ NO TOKEN FOUND ! ]
Set an environment variable named 'econtoken', or put econtoken=<your token> in a .env file next to main.py.

After, with a valid token but intents not yet enabled in the portal — the error that was being hidden all along:

discord.errors.PrivilegedIntentsRequired: Shard ID None is requesting privileged intents that have not
been explicitly enabled in the developer portal.

Enabling the three intents then boots the bot cleanly through to on_ready:

[ VALIDATING SETTINGS . . . ]
...
[ LOADED USER DATA ]
[ INITIATING AUTO-SAVE . . . ]
--- LOGGED IN AS econbot ---

No behaviour change on a healthy startup path.