P14-T01 — Feedback domain and contracts

Status: LOCAL_DONE on codex/phase-14-station-feedback (phase PR pending, first push with this commit). Issue: #28 (slice 1 of 5; issue stays open until the phase PR merges). No live-provider contact; no handlers, migrations or paths in this slice.

Slice acceptance (frozen before coding)

• T01 (this commit) — frozen semantics: integer 1–5 ratings, one current rating per account/target; 280-scalar plain text with trim + CRLF normalization (replies share the limit, depth one); floor basis-point agreement with null for zero votes; station + fuel target shape; revision/audit rules documentary. Executable vectors in contracts/testdata/feedback/ replayed by Go; Kotlin/Swift parity for rating + agreement (+ shared 280 text boundary); additive OpenAPI preview schemas (no paths).

What changed

• contracts/testdata/feedback/ — 18 golden vectors (text valid/280/281/empty/accents/emoji/combining/CRLF/invalid-UTF8, rating 5/1/0/6, agreement 2-1/0-3/3-0/0-0, revision supersede), every scalar count verified against normalized counting before commit.
• backend/internal/modules/feedback/domain/ — stdlib-only values (Rating, CommentText, Agreement, Target), frozen bounds, stable verdict codes; fixture-shape + replay suites (vectors and code cannot drift).
• domain/.../portable/PortableFeedback.kt + test — range + floor math + null-zero + negative refusal + shared 280 hook.
• iosApp/.../PortableFeedback.swift + XCTest — 1:1 transcription (precondition mirrors require); implemented-unverified per owner decision.
• contracts/openapi/v1.yaml — additive FeedbackRating, FeedbackComment, FeedbackAgreement (nullable bps for no-votes); 6 api vectors keep apicontract green.

RED → GREEN

• RED proven by loosening the scalar bound by one: the 281 fixture replays ok instead of text-too-long; GREEN on restore.
• Vector-count mismatches (3 hand-counted scalars) found and fixed pre-commit by programmatic verification.

Validation (exact commands, this host)

cd backend && GOTOOLCHAIN=go1.27.1 go test -count=1 ./internal/modules/feedback/... \
  && GOTOOLCHAIN=go1.27.1 go test -count=1 ./internal/platform/apicontract/...
./gradlew :domain:test --no-daemon
bash scripts/check-mobile.sh
make quick-verify
git diff --check

Outcome: Go 7 suites incl. 18/18 fixture replays green; Kotlin PortableFeedbackTest 5/5; check-mobile full ok (Android green, Swift skip recorded outstanding); vacuum 0/0/14 info; apicontract ok; quick-verify selection=full ok; diff --check clean; secrets scan clean.

Limits (not claimed)

• No ratings/comments persistence, transport, jobs or projections (P14-T02…T04); no moderation/privacy (P14-T05).
• Swift compiles/runs on macOS only (release horizon).
• Platform string-model note: Go rejects invalid UTF-8; Kotlin counts lone surrogates singly; Swift counts scalars — vectors document the cases, each platform behaves per its model.

Rollback

Pure addition (fixtures, one Go package, two Kotlin files, two Swift files, preview schemas + vectors): deleting them restores the tree. No migration, no flag.

Next

P14-T02 rating transactions + aggregates (#29, same branch). Issue #28 stays open until the phase PR merges.