feat: interactive autograded starter workspace (Module 03)

[IshmaelRogers]

What this does

Converts Module 03 (Web Platform: JavaScript Foundations) from an LMS content dump into an
interactive, autograded starter workspace, mirroring the approved Module 04 reference template.
Learners open an exercise, read its README.md, implement the // TODOs in src/, run the tests, and
push — the Autograde GitHub Action reports a per-exercise score and comments it on the PR.

Structure

• Toolchain (one root): package.json (vitest + jsdom, ES modules, plain .js), vitest.config.ts
  (Node default; DOM labs opt into jsdom per-file), scripts/grade.mjs (groups results by exercise
  folder under labs//assignments/; no tsc gate — typeGate = { ok: true }, the tests are the gate),
  .github/workflows/autograde.yml, .gitignore, rewritten root README.md, refreshed .devcontainer.
• Removed LMS-duplicated content: Lesson_*.md, LEARNER_GUIDE.md, MODULE_SYLLABUS.md, flat
  labs/*.md + labs/README.md, assignments/README.md, and the flat capstone-brief.md (folded into
  assignments/capstone/README.md). Kept resources/, .devcontainer/, and both
  *submission-template*.md files.
• No answer keys shipped. Each src/ is starter code with // TODOs; each tests/ is the spec.

Exercises (13 folders)

Folder	Autograded core
labs/lab-00-environment	analyzeResource — classify a Network entry, render-blocking + transfer size
labs/lab-01-page-load	firstPaintBlockers / criticalPath over a resource list
labs/lab-02-login-form	validate + initLoginForm (jsdom: selector/passing/preventDefault)
labs/lab-03-layout	auditLayout — flag the four box-model bugs from CSS declarations
labs/lab-04-js-runtime	fix coercion / var loop-capture / shared state / this
labs/lab-05-modernize	ES6+ utils, behaviour-preserving (the || vs ?? trap)
labs/lab-06-async-eventloop	eventLoopOrder; callbacks → async/await; chunk yields
labs/lab-07-data-structures	joinFast (Map) + dedupFast (Set), matched against the slow versions
labs/lab-08-search	binarySearch + memoize + debounce (fake timers)
labs/lab-09-http-rest	fix a fetch client that treats 4xx/5xx as success (stubbed fetch)
labs/lab-10-dns-tcp	parseCurlTiming + attributeSlowness to a layer
labs/lab-11-rendering	layoutTriggers guard + batched-read/write scheduleUpdates
assignments/capstone	integrated diagnostics toolkit across all six layers

Harness & dependencies

• vitest ^2.1.8 + jsdom ^25.0.1 (dev only). Plain .js ES modules with JSDoc — no TypeScript,
  so the tsc type gate from Module 04's grader is dropped and the tests are the sole gate.

Verification

• Stubs (RED): node scripts/grade.mjs → 16/81 tests (20%), exit 1, every exercise ❌.
  (A handful of stub defaults coincidentally satisfy negative/empty-case assertions; the suite is RED overall.)
• Reference solution (GREEN): implemented every // TODO in a throwaway copy outside the repo →
  81/81 tests (100%), exit 0, all 13 exercises ✅. Temp copy deleted; no solutions are in this branch.

Honest notes on autogradability

These labs are DevTools/browser-investigation heavy (Network waterfalls, Performance traces, box-model
overlays, dig/ping/traceroute). Those hands-on steps can't be autograded, so each lab distills its
autogradable core — a pure function or jsdom-assertable DOM behaviour — and the README directs the
remaining investigative deliverables to the LMS notebook. The most investigation-bound labs (00, 01, 03,
10) are graded on the reasoning artifact (classify a resource, list blockers, audit declarations, parse
and attribute curl timings) rather than live tool output. Every folder still has a README, real starter
src/, and at least five passing tests.

[github-actions]

Forge SWEXP — Module 03 autograde

Score: 16/81 tests (20%)

Exercise	Tests	Status
assignments/capstone	0/7	❌
labs/lab-00-environment	4/8	❌
labs/lab-01-page-load	1/5	❌
labs/lab-02-login-form	4/8	❌
labs/lab-03-layout	1/6	❌
labs/lab-04-js-runtime	1/6	❌
labs/lab-05-modernize	0/6	❌
labs/lab-06-async-eventloop	0/6	❌
labs/lab-07-data-structures	0/5	❌
labs/lab-08-search	0/8	❌
labs/lab-09-http-rest	2/5	❌
labs/lab-10-dns-tcp	1/5	❌
labs/lab-11-rendering	2/6	❌

Keep going — open each exercise folder, implement the // TODOs in its src/, and run npm test. The tests in each tests/ folder are the spec.