The build step part's request names both forms; the three build seats' contracts regenerated (issue 1966)

The compose job's `request` description now says it is the request object or the JSON string "gzip+base64:" followed by the
base64 of the gzip-compressed object, as ADR 0634 §1 puts a seat's messages in its contract. The field stays `any`;
seatgen regenerated node-build-go, node-build-node and node-build-image (Go and TypeScript), and its -check is clean.
ask.go's comment says the checker packs every request it sends.

Delivery: an old holder of node-build-go refuses the packed ask loudly (it holds no request object) until it runs the new
mesh-build-go; the checker is built by mesh-build-go after it (module graph edge), and every check composing ace or novox
fails today anyway.

Claude-Session: https://claude.ai/code/session_01NcbgfFfQ4Z9UE5jK32PmE5

contracts/go/seats/nodebuildgo/contract.go

@@ -485,7 +485,7 @@ type StepAskCompose struct {
 	Fetch   Fetch  `json:"fetch"`
 	Package string `json:"package"`
 	Reader  string `json:"reader,omitempty"`
-	// the compose-candidate request
+	// the compose-candidate request, in one of two forms: the request as a JSON object, or, for one near the bus's message limit, a JSON string "gzip+base64:" followed by the base64 of the request object gzip-compressed; a holder that does not know the packed form refuses it, naming that it holds no request object
 	Request any `json:"request"`
 }
 

contracts/go/seats/nodebuildimage/contract.go

@@ -485,7 +485,7 @@ type StepAskCompose struct {
 	Fetch   Fetch  `json:"fetch"`
 	Package string `json:"package"`
 	Reader  string `json:"reader,omitempty"`
-	// the compose-candidate request
+	// the compose-candidate request, in one of two forms: the request as a JSON object, or, for one near the bus's message limit, a JSON string "gzip+base64:" followed by the base64 of the request object gzip-compressed; a holder that does not know the packed form refuses it, naming that it holds no request object
 	Request any `json:"request"`
 }
 

contracts/go/seats/nodebuildnode/contract.go

@@ -485,7 +485,7 @@ type StepAskCompose struct {
 	Fetch   Fetch  `json:"fetch"`
 	Package string `json:"package"`
 	Reader  string `json:"reader,omitempty"`
-	// the compose-candidate request
+	// the compose-candidate request, in one of two forms: the request as a JSON object, or, for one near the bus's message limit, a JSON string "gzip+base64:" followed by the base64 of the request object gzip-compressed; a holder that does not know the packed form refuses it, naming that it holds no request object
 	Request any `json:"request"`
 }
 

contracts/parts/build-step.json

@@ -161,7 +161,7 @@
               "type": "string"
             },
             "request": {
-              "description": "the compose-candidate request"
+              "description": "the compose-candidate request, in one of two forms: the request as a JSON object, or, for one near the bus's message limit, a JSON string \"gzip+base64:\" followed by the base64 of the request object gzip-compressed; a holder that does not know the packed form refuses it, naming that it holds no request object"
             },
             "reader": {
               "type": "string"

contracts/ts/seats/nodebuildgo/src/parts/build-step.ts

@@ -293,7 +293,7 @@ export interface StepAskCompose {
   "fetch": Fetch;
   "package": string;
   "reader"?: string;
-  /** the compose-candidate request */
+  /** the compose-candidate request, in one of two forms: the request as a JSON object, or, for one near the bus's message limit, a JSON string "gzip+base64:" followed by the base64 of the request object gzip-compressed; a holder that does not know the packed form refuses it, naming that it holds no request object */
   "request": unknown;
 }
 

contracts/ts/seats/nodebuildimage/src/parts/build-step.ts

@@ -293,7 +293,7 @@ export interface StepAskCompose {
   "fetch": Fetch;
   "package": string;
   "reader"?: string;
-  /** the compose-candidate request */
+  /** the compose-candidate request, in one of two forms: the request as a JSON object, or, for one near the bus's message limit, a JSON string "gzip+base64:" followed by the base64 of the request object gzip-compressed; a holder that does not know the packed form refuses it, naming that it holds no request object */
   "request": unknown;
 }
 

contracts/ts/seats/nodebuildnode/src/parts/build-step.ts

@@ -293,7 +293,7 @@ export interface StepAskCompose {
   "fetch": Fetch;
   "package": string;
   "reader"?: string;
-  /** the compose-candidate request */
+  /** the compose-candidate request, in one of two forms: the request as a JSON object, or, for one near the bus's message limit, a JSON string "gzip+base64:" followed by the base64 of the request object gzip-compressed; a holder that does not know the packed form refuses it, naming that it holds no request object */
   "request": unknown;
 }
 

sdk/buildstep/ask.go

@@ -288,8 +288,9 @@ type ComposeJob struct {
 	Fetch   Fetch  `json:"fetch"`
 	Dir     string `json:"dir"`
 	Package string `json:"package"`
-	// Request is the composer's request: a JSON object, or, for one near the bus's message limit (issue 1966), a JSON
+	// Request is the composer's request: a JSON object, or a JSON string PackedRequestPrefix + the base64 of the object
-	// string PackedRequestPrefix + the base64 of the object gzip-compressed. The part types it `any`, so both fit it; a
+	// gzip-compressed (issue 1966; the checker packs every request it sends, and
+	// the part's `request` describes both forms). The part types it `any`, so both fit it; a
 	// build module that does not know the packed form refuses the ask naming that it holds no request object.
 	Request json.RawMessage `json:"request"`
 	Reader  string          `json:"reader,omitempty"`