🔒 Fix hardcoded dummy secrets in docstrings

[shivan4030]

🎯 What: The security scanner flagged a hardcoded client secret vulnerability. This was a false positive as it was a dummy string (your_client_secret) used within a docstring example in auth_helpers.py. This PR changes these dummy strings to uppercase placeholders (e.g. YOUR_CLIENT_SECRET). It also fixes a broken parameter syntax redirect to redirect_uri in the same docstring.
⚠️ Risk: While not an actual vulnerability, leaving lowercase dummy secrets in docstrings triggers security scanner warnings, creating noise and potential confusion for developers who might copy-paste them.
🛡️ Solution: By using standard uppercase placeholders (YOUR_CLIENT_SECRET, YOUR_CLIENT_ID, YOUR_API_KEY, YOUR_TOKEN), the security scanners will no longer flag these as valid hardcoded secrets, and it's clearer to developers that these are placeholders meant to be replaced with actual secure configurations.

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PR created automatically by Jules for task 5402171254827060337 started by @shivan4030

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