feat: add REST API and interactive React dashboard

[honeydew78]

…rd for visualization

[github-actions]

🛡️ Diff-Guard Architectural Risk Report

PR: #0 | Status: 🟡 MEDIUM RISK | Risk Score: 20/100

🔍 Modified Semantic Entities

File	Entity	Change Type
app.py	parse_github_url()	ADDED
app.py	api_analyze()	ADDED

🕸️ Architectural Blast Radius

⚠️ 2 downstream files are directly or transitively affected:

Modified File	Impacted Downstream Files (Dependency Path)
app.py	app.py ➔ cli.py
app.py	app.py ➔ tests/test_api.py