docs(glossary): rewrite BDD page with process, Gherkin examples, tools a table and a keploy section

[amaan-bhati]

What has changed?

Rewrite of the BDD glossary page (/docs/concepts/reference/glossary/behaviour-driven-development/).

• New title and meta: "What is BDD (Behavior-Driven Development)?"
• BDD framed as a collaboration process first; adds history, BDD vs BDD testing, 3 practices + 6-step lifecycle
• Full Gherkin anatomy (Feature, Background, Scenario Outline, Examples, tags) with a negative scenario
• Empty Java stubs replaced with working Cucumber + Selenium step definitions; added Python behave example
• New "BDD for API testing" section (REST checkout in Gherkin + behave)
• Tools table: SpecFlow marked end-of-life (Dec 31, 2024), Reqnroll listed as .NET successor, "Microsoft Studio" removed
• TDD vs BDD vs ATDD comparison table; outdated BDD vs TDD image dropped
• Real limitations and "when not to use" list; new best practices section
• New "How Keploy complements BDD" section with CTAs to the API test generator and install docs
• FAQs expanded from 6 to 10; contextual internal links added in body copy
• Sentence-case headings, no em dashes, Prettier formatted

Type of change

• Documentation update

How Has This Been Tested?

npx prettier --check passes. All internal link targets verified to exist in version-4.0.0. npm run build to be run locally before merge.

Checklist:

• My code follows the style guidelines of this project.
• I have performed a self-review of my own code.

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[nehagup]

Big improvement over the old page. The working step definitions, the API section and the SpecFlow → Reqnroll correction are exactly what this page needed, and the Keploy section is positioned well (BDD for intended behaviour, Keploy for regression coverage from real traffic). I checked all the internal links and the new image, and they return 200. Some edits:

1. Put the hyphens back. "Behavior driven development", "test driven development", "acceptance test driven development" and "domain driven design" all need a hyphen ("behavior-driven development"). The no-em-dash rule doesn't cover hyphens, and the unhyphenated form looks like an error to the developers reading this. Keep "behaviour driven development" as the alternate spelling, hyphenated too.
2. The title in the PR description doesn't match the diff. The description says the new title is "What is BDD (Behavior-Driven Development)?", but the frontmatter has "Behavior driven development (BDD): process, examples and tools". Pick one. I'd lean toward the "What is…" form for the glossary query intent, keeping "examples and tools" in the description.
3. Java example leaks browsers. driver.quit() sits after the assertion in each @Then, so any failing assertion leaves Chrome running. Readers copy these snippets, so move setup and teardown into @Before/@After hooks. Better yet, don't create the driver in a Given at all.
4. Python example: add resp.raise_for_status() (or an assert) in step_create_cart. Otherwise a failed cart creation shows up as a confusing KeyError: 'id'.
5. Dark mode: the new image is bdd-process-light.webp. Is there a dark variant? If so, it's worth switching to a light/dark pair so the image works in dark mode.

Please run npm run build before merge, as noted in the description.