Add a public-facing README with production-ready project documentation

[Copilot]

This updates an empty README.md into a public-facing project document aligned with OSS best practices. The new content is structured for fast onboarding, operational clarity, and safe configuration by external contributors.

• Problem addressed

  • Replaced a blank README with a complete, scan-friendly overview of what the app is, how it works, and how to run it.

• Documentation structure added

  • Project overview and feature set
  • Tech stack and repository layout
  • Prerequisites and environment configuration
  • Local development commands and script reference
  • Deployment model (GitHub Actions + Firebase Hosting)
  • Contribution expectations

• Operational/security clarity

  • Documented required environment variables (OPENAI_API_KEY, APP_URL, DEFAULT_AI_MODEL)
  • Added explicit note about frontend runtime key usage to avoid unsafe deployment assumptions

• Example (from new README usage flow)

  npm ci
  npm run start

[Copilot]

Pull request overview

Replaces the previously empty README.md with a public-facing project document describing the app’s purpose, stack, setup, scripts, deployment flow, and contribution expectations.

Changes:

• Added a project overview, feature list, and tech stack summary
• Documented local development commands, quality checks, and available npm scripts
• Documented environment variables and the Firebase Hosting CI/CD deployment model

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[Copilot]

The README instructs copying .env.example to .env, but the app/tooling in this repo doesn’t load .env (no dotenv usage). As written, users may expect npm run start/npm run build to pick up .env automatically, but the only documented injection path is via --define (see npm run dev). Update the README to either (a) document exporting env vars + using npm run dev, or (b) add and document a .env loader so cp .env.example .env actually works.

[Copilot]

APP_URL is listed as an environment value, but it isn’t referenced anywhere in the codebase. Either remove it from the README (and possibly .env.example) or document the exact place it’s consumed so contributors don’t spend time configuring an unused variable.

Suggested change

- `APP_URL` (runtime app URL)

[Copilot]

The warning about initializing OpenAI calls in the browser is easy to overlook and understates the risk: because OPENAI_API_KEY is injected via build-time define, it will be bundled into client JS and exposed to every user. Please make the README explicit that this is not safe for production and recommend moving OpenAI calls to a server-side proxy/Cloud Function (or remove references to deploying with a real key).

[Copilot]

The deployment section says OPENAI_API_KEY is a required GitHub secret, but the current workflow only sets it as an environment variable for npm run build and does not pass a --define override. Given the code reads a build-time global OPENAI_API_KEY, this secret likely has no effect on the deployed bundle. Either update the README to reflect how the key is actually injected during CI builds, or adjust the workflow/build config accordingly and document that approach here.

Suggested change

	- `OPENAI_API_KEY`
	- `FIREBASE_SERVICE_ACCOUNT`
	- `FIREBASE_SERVICE_ACCOUNT`
	`OPENAI_API_KEY` is used for local/development configuration, but the current CI deployment flow does not inject it into the production bundle as a build-time define. If CI-based OpenAI access is needed later, update the workflow/build command to pass the define explicitly and document that injection mechanism here.