docs: Align CLI command names, API key env vars, and outdated repository URLs

[CodeMaverick-143]

Problem Description

There are several confusing discrepancies between documentation and code:

1. CLI Command Name Mismatch:
   • README.md tells users to run: insight .
   • INSTRUCTION.md tells users to run: insight-cli .
   • setup.py registers only console_scripts: ["insight-cli=insight.cli:main"]. Running insight . as told in README.md fails with command not found: insight.
2. API Key Environment Variable Mismatch:
   • README.md instructs users to export GEMINI_API_KEY="...".
   • INSTRUCTION.md instructs users to export GOOGLE_API_KEY="...".
   • insight/detector.py checks only GOOGLE_API_KEY. Users following README.md encounter an error.
3. Outdated URLs & Links:
   • setup.py lists url="https://github.com/ExplainHub/Insight-Py"
   • README.md lists https://github.com/XplnHUB/Insight-Py.git
   • Git remote origin is https://github.com/ferrix-lab/Insight-Py.git
   • CONTRIBUTING.md line 9 contains a Google search URL: https://www.google.com/search?q=CODE_OF_CONDUCT.md instead of a relative link [Code of Conduct](CODE_OF_CONDUCT.md).

Proposed Solution

1. Register both insight and insight-cli console scripts in setup.py:

   "console_scripts": [
       "insight=insight.cli:main",
       "insight-cli=insight.cli:main",
   ]

2. Accept both GOOGLE_API_KEY and GEMINI_API_KEY in detector.py:

   api_key = os.environ.get("GOOGLE_API_KEY") or os.environ.get("GEMINI_API_KEY")

3. Update all URLs across setup.py, README.md, and CONTRIBUTING.md to point to ferrix-lab/Insight-Py.