fix: resolve Node server boot crashes, missing routes, and prediction stats

[onkar0127]

RESOLVE #836

PR Description:

Problem Summary

Following recent merges, the Node.js Express server was failing to boot and crashed immediately on startup. In addition, there were multiple missing routes and engine scripts that caused 404/500 errors on dashboard pages, along with a database query lookup bug on the /stats endpoint.

This PR cleans up Express route initialization order, stubs the missing visual routes and poisoning defense python components, aligns CLI arguments across Python detectors, and fixes database lookup models.

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Key Changes

1. Core Express Initialization & Server Boot Fixes

• File: backend/server.js
• Reordered routes to initialize the Express app instance before mounting any middleware or custom routers, resolving the fatal ReferenceError: app is not defined.
• Resolved a syntax error on line 48 caused by a duplicate, unclosed logStartupTime definition.
• Cleaned up duplicate imports and route mounting for the EvoMail routes.
• Mounted the saltingRoutes router under /api/salting.

2. Added Missing Router & Scripts

• Files: backend/routes/visualRoutes.js, backend/llm_poisoning_defense.py
• Created visualRoutes.js to prevent the import crash when require('./routes/visualRoutes') is resolved on server boot.
• Created llm_poisoning_defense.py to handle command execution (--command and --params args) for the newly introduced poisoning defense endpoints (/validate, /detect, /train, /status).

3. Restructured Python CLI Support

• Files: backend/text_salting_detector.py, backend/visual_detector.py, backend/routes/saltingRoutes.js
• Refactored main execution hooks to parse CLI parameters cleanly when invoked by the Express child process, printing JSON outputs.
• Fixed path extension error in saltingRoutes.js (pointing to .js instead of .py).

4. Fixed Stats Endpoint Crash

• File: backend/routes/predictionRoutes.js
• Replaced the undefined Prediction model in the /stats endpoint with the correct History collection lookup, and mapped userId to the correct schema parameter user.

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Verification and Testing

• Checked syntax validation on all modified JS files (node --check backend/server.js passes with zero errors).
• Verified compilation checks on modified Python scripts (python -m py_compile passes with zero errors).
• Ran unit tests inside the virtual environment:
  • test_crypto_utils.py (3 Passed)
  • test_sqlite_concurrency.py (1 Passed)
  • test_spam_words.py (4 Passed)

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[onkar0127]

@Userunknown84 let me know about this PR!!

[Userunknown84]

Some code delete i comment on it.

[Userunknown84]

This route is also delete

[Userunknown84]

Few things i coment on it please check rest code is fine i see .

[Userunknown84]

Merge conflict and some code delete so kindly fix then i will merge