[FEAT]: Add structured logging across the project and replace print() diagnostics

[SHANKAR8983]

Description

The project currently uses print() statements throughout the codebase for diagnostics and debugging.

While useful during development, print() has several limitations in production environments:

• No timestamps
• No severity levels (INFO, WARNING, ERROR)
• No module/source identification
• Cannot easily redirect logs to files or external monitoring systems

This PR introduces structured logging to improve observability, debugging, and production readiness of the project.

Rationale

A centralized logging system provides several benefits:

• Timestamped logs for better debugging
• Severity levels (INFO, DEBUG, ERROR, WARNING)
• Consistent logging format across modules
• Ability to route logs to files or monitoring tools
• Cleaner debugging and production diagnostics

Changes Made

1. Created src/logger.py — Centralized logging utility

import logging

def setup_logger(name: str):
    logger = logging.getLogger(name)

    if logger.handlers:
        return logger

    logger.setLevel(logging.INFO)

    handler = logging.StreamHandler()
    formatter = logging.Formatter(
        "%(asctime)s | %(levelname)s | %(name)s | %(message)s",
        datefmt="%Y-%m-%d %H:%M:%S"
    )
    handler.setFormatter(formatter)
    logger.addHandler(handler)
    return logger

2. Updated src/llm.py

Before:

print("\t[LOG] Resulting JSON created from the input text:")
print(json.dumps(self._json, indent=2))
print(f"\t[LOG]: Formating plural values for JSON, [For input {plural_value}]...")

After:

logger.info("Resulting JSON created from the input text:")
logger.info(json.dumps(self._json, indent=2))
logger.info(f"Formatting plural values for JSON, input: {plural_value}")

3. Updated src/file_manipulator.py

Before:

print("[1] Received request from frontend.")
print(f"[2] PDF template path: {pdf_form_path}")
print(f"Error: PDF template not found at {pdf_form_path}")

After:

logger.info("Received request from frontend.")
logger.info(f"PDF template path: {pdf_form_path}")
logger.error(f"PDF template not found at {pdf_form_path}")

Sample Log Output

2026-03-28 08:30:01 | INFO | src.llm | Resulting JSON created from the input text:
2026-03-28 08:30:01 | INFO | src.llm | Formatting plural values for JSON, input: ...
2026-03-28 08:30:01 | INFO | src.file_manipulator | Process Complete.
2026-03-28 08:30:01 | ERROR | src.file_manipulator | PDF template not found at ...

Closes #220