M1: contracts and vectors (SPEC v0.1, schema 1)

contracts/openapi.yaml (OpenAPI 3.1, E-1..E-33, error shape and the
exhaustive error code enum, device bearer scheme), contracts/schema/
server-v1.sql (SPEC §14.1 verbatim), seven test-vector files per §14.5.5,
80 examples (every JSON body of §14.3.4, every error code, sync pull/push,
every FCM push type), and tools/contracts-check.py (stdlib-only reference
of §9.1, §9.3, §9.4 and §14.5.4 plus shape checks; the M1 gate).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

contracts/examples/errors/account_not_empty.json

@@ -0,0 +1,5 @@
+{
+  "code": "account_not_empty",
+  "message": "account is referenced by expenses, settlements or templates",
+  "field": null
+}

contracts/examples/errors/batch_too_large.json

@@ -0,0 +1,5 @@
+{
+  "code": "batch_too_large",
+  "message": "more than 100 mutations",
+  "field": "mutations"
+}

contracts/examples/errors/cannot_revoke_current_device.json

@@ -0,0 +1,5 @@
+{
+  "code": "cannot_revoke_current_device",
+  "message": "cannot revoke the calling device",
+  "field": null
+}

contracts/examples/errors/category_in_use.json

@@ -0,0 +1,5 @@
+{
+  "code": "category_in_use",
+  "message": "category is used by expenses or templates",
+  "field": null
+}

contracts/examples/errors/category_is_default.json

@@ -0,0 +1,5 @@
+{
+  "code": "category_is_default",
+  "message": "default categories cannot be deleted",
+  "field": null
+}

contracts/examples/errors/cursor_ahead.json

@@ -0,0 +1,5 @@
+{
+  "code": "cursor_ahead",
+  "message": "since is greater than the current sequence value",
+  "field": "since"
+}

contracts/examples/errors/device_revoked.json

@@ -0,0 +1,5 @@
+{
+  "code": "device_revoked",
+  "message": "device is revoked",
+  "field": null
+}

contracts/examples/errors/forbidden.json

@@ -0,0 +1,5 @@
+{
+  "code": "forbidden",
+  "message": "role member may not manage invites",
+  "field": null
+}

contracts/examples/errors/household_full.json

@@ -0,0 +1,5 @@
+{
+  "code": "household_full",
+  "message": "the household already has two users",
+  "field": null
+}

contracts/examples/errors/household_incomplete.json

@@ -0,0 +1,5 @@
+{
+  "code": "household_incomplete",
+  "message": "the partner has not joined yet",
+  "field": null
+}

contracts/examples/errors/image_invalid.json

@@ -0,0 +1,5 @@
+{
+  "code": "image_invalid",
+  "message": "picture cannot be decoded",
+  "field": null
+}

contracts/examples/errors/internal.json

@@ -0,0 +1,5 @@
+{
+  "code": "internal",
+  "message": "internal error, request id 0192a0ff-0000-7000-8000-000000000001",
+  "field": null
+}

contracts/examples/errors/invalid_request.json

@@ -0,0 +1,5 @@
+{
+  "code": "invalid_request",
+  "message": "missing field `device_name`",
+  "field": "device_name"
+}

contracts/examples/errors/invite_invalid.json

@@ -0,0 +1,5 @@
+{
+  "code": "invite_invalid",
+  "message": "invite code is not valid",
+  "field": null
+}

contracts/examples/errors/name_taken.json

@@ -0,0 +1,5 @@
+{
+  "code": "name_taken",
+  "message": "an account with this name exists",
+  "field": "name"
+}

contracts/examples/errors/no_accounts.json

@@ -0,0 +1,5 @@
+{
+  "code": "no_accounts",
+  "message": "no_accounts",
+  "field": null
+}

contracts/examples/errors/not_found.json

@@ -0,0 +1,5 @@
+{
+  "code": "not_found",
+  "message": "no such account",
+  "field": null
+}

contracts/examples/errors/not_implemented.json

@@ -0,0 +1,5 @@
+{
+  "code": "not_implemented",
+  "message": "not implemented",
+  "field": null
+}

contracts/examples/errors/payload_too_large.json

@@ -0,0 +1,5 @@
+{
+  "code": "payload_too_large",
+  "message": "body exceeds 1 MiB",
+  "field": null
+}

contracts/examples/errors/protocol_unsupported.json

@@ -0,0 +1,5 @@
+{
+  "code": "protocol_unsupported",
+  "message": "X-Kvitt-Protocol must be 1",
+  "field": null
+}

contracts/examples/errors/rate_limited.json

@@ -0,0 +1,5 @@
+{
+  "code": "rate_limited",
+  "message": "too many requests",
+  "field": null
+}

contracts/examples/errors/unauthorized.json

@@ -0,0 +1,5 @@
+{
+  "code": "unauthorized",
+  "message": "missing or unknown bearer token",
+  "field": null
+}

contracts/examples/errors/unavailable.json

@@ -0,0 +1,5 @@
+{
+  "code": "unavailable",
+  "message": "database busy",
+  "field": null
+}

contracts/examples/errors/unsupported_media_type.json

@@ -0,0 +1,5 @@
+{
+  "code": "unsupported_media_type",
+  "message": "picture must be image/jpeg, image/png or image/webp",
+  "field": null
+}

contracts/examples/errors/validation_failed.json

@@ -0,0 +1,5 @@
+{
+  "code": "validation_failed",
+  "message": "amount_ore must be between 1 and 1000000000",
+  "field": "amount_ore"
+}