CI: INIT_FILEUPLOAD_PARITY_GATE default-on in ci-fast (prereq #2004 ✅)

[PurHur]

Problem

#1902 flipped INIT_SESSIONSWEB_PARITY_GATE=1 after phpc init --profile sessionsweb template parity landed. #2004 will add phpc init --profile fileupload with script/check-init-fileupload-parity.sh, but without a gate-flip issue the checker stays opt-in and templates can drift from examples/006-FileUploadWeb/.

Goal

1. Land DevEx: phpc init --profile fileupload scaffold (006-FileUploadWeb parity) #2004 (template + PhpcInitFileUploadTest)
2. Wire INIT_FILEUPLOAD_PARITY_GATE=1 default in script/ci-defaults.env + ci-fast.sh
3. Document in phpc doctor --gates and docs/local-ci-matrix.md

Acceptance criteria

./script/ci-fast.sh --filter PhpcInitFileUpload
php script/check-init-fileupload-parity.sh   # no env override

Verification (local / Docker only)

docker run --rm -v "$(pwd):/compiler" -w /compiler php-compiler:22.04-dev \
  ./script/ci-fast.sh --filter PhpcInitFileUpload

No GitHub Actions.

Dependencies

• DevEx: phpc init --profile fileupload scaffold (006-FileUploadWeb parity) #2004 — init profile implementation
• Examples: 006-FileUploadWeb — multipart $_FILES reference + AOT execute smoke #1999 ✅ — canonical example tree

Links

• Sibling: DevEx: check-init-sessionsweb-parity.sh — template ↔ examples/005-SessionsWeb (#695 pattern) #1902 (sessionsweb parity gate)
• ROADMAP 🗺️ ROADMAP: Self-host + web-capable PHP subset (living) #78

[PurHur]

Prerequisite landed (batch 108)

#2004 ✅ closed · PR #2036 merged · script/check-init-fileupload-parity.sh on master.

Ready for implementation: flip INIT_FILEUPLOAD_PARITY_GATE default 0 → 1 in script/ci-defaults.env, confirm ci-common.sh + CiScriptsTest.php + docs/local-ci-matrix.md + phpc doctor --gates.

Verify locally (Docker):

docker run --rm -v "$(pwd):/compiler" -w /compiler php-compiler:22.04-dev \
  bash -lc 'INIT_FILEUPLOAD_PARITY_GATE=1 ./script/ci-fast.sh --filter PhpcInitFileUpload'

Blocks drift between templates/init-fileupload/ and examples/006-FileUploadWeb/. Parent: #78 batch 108 gate-flip track.

[PurHur]

Prerequisite landed (batch 109)

Checker/scaffold issue is closed on master. This issue is ready for a small implementation PR: flip the gate default in script/ci-defaults.env + wire in script/ci-fast.sh (ci_run_inventory_checks), then run ./script/ci-fast.sh in Docker.

Parent roadmap: #78 batch 109.