Docs: GETTING-STARTED optional step — 005-SessionsWeb session flash demo

[PurHur]

Problem

docs/GETTING-STARTED.md walks presenters through 000 native binary, 003-MiniWebApp VM/AOT, and self-host smoke, but not 005-SessionsWeb. The shipped example is on master (#1881 ✅) with VM curls in examples/README.md and make examples-sessions-smoke (#1887 ✅), yet first-time contributors still miss the two-request cookie story when demoing “real” session state.

Goal

Add an optional numbered step (after MiniWebApp or before self-host) that mirrors examples/005-SessionsWeb/README.md:

./phpc serve examples/005-SessionsWeb
jar=/tmp/phpc-sessionsweb.jar
curl -s -c "$jar" 'http://127.0.0.1:8080/example.php'
curl -s -b "$jar" -c "$jar" -X POST -d 'message=Saved' 'http://127.0.0.1:8080/example.php'
curl -s -b "$jar" 'http://127.0.0.1:8080/example.php'   # expect flash HTML

Mention AOT/deploy as “when green” links only (#1891, #1893) — do not block the VM presenter path.

Scope

Piece	Path
Guide	docs/GETTING-STARTED.md — new subsection + talking point
Cross-link	examples/README.md § 005, #1903 phpc doctor --gates
Status site	Optional one-liner in docs/pages/development-status.md (no matrix links)

Out of scope: implementing AOT execute (#1891); phpc init --profile sessionsweb (#1886).

Acceptance criteria

• GETTING-STARTED lists VM session demo commands copy-paste ready
• Links Examples: 005-SessionsWeb — session_start + flash message reference app #1881, Testing: 005-SessionsWeb in examples-web-smoke + ExamplesCompileTest #1887, Testing: 005-SessionsWeb AOT link + two-request CGI execute smoke #1891, Testing: 005-SessionsWeb phpc deploy + PHPC_DEPLOY_ROOT CGI smoke #1893, ROADMAP 🗺️ ROADMAP: Self-host + web-capable PHP subset (living) #78
• grep -q '005-SessionsWeb' docs/GETTING-STARTED.md in a doc check or manual review

Verification (local / Docker only)

make examples-sessions-smoke
# or:
SESSIONS_WEB_SMOKE_GATE=1 ./script/examples-web-smoke.sh --sessions-only
docker run --rm -v "$(pwd):/compiler" -w /compiler php-compiler:22.04-dev \
  make examples-sessions-smoke

No GitHub Actions (#394 ✅).

Dependencies

• Examples: 005-SessionsWeb — session_start + flash message reference app #1881 ✅ example tree
• Testing: 005-SessionsWeb in examples-web-smoke + ExamplesCompileTest #1887 ✅ VM smoke gate

Links

• ROADMAP 🗺️ ROADMAP: Self-host + web-capable PHP subset (living) #78 Phase 4 Polish
• Init profile follow-up: DevEx: phpc init --profile sessionsweb (005-SessionsWeb scaffold) #1886 / DevEx: check-init-sessionsweb-parity.sh — template ↔ examples/005-SessionsWeb (#695 pattern) #1902

[PurHur]

Closed via merged PR #1986: GETTING-STARTED §5 SessionsWeb VM flash demo + examples/README cross-link.