chore: pi family 0.85.1 -> 0.87.1 (finishTurn, transcript contexts, typebox 1.3.27)

Mechanical fallout only; semantic deltas flagged in the wave report:
- shouldStopAfterTurn -> finishTurn ({action:'end'} wrap; loop order verified
  equivalent for Wave C stranding)
- transcript rework: seeded leading SystemMessage filtered at both
  state.messages read seams (ui-stream settleWith, pi-run slice); prompt
  and tool declarations now ride the transcript
- streamOnce sites normalizeContext() (Context -> TranscriptContext)
- AgentToolResult details / ToolCall.arguments JsonValue narrowing (casts)
- AUTH_PROVIDER_KEYS regenerated (meta added); glm-5.3-flash price pin
  follows the 0.87.1 catalog (0.15/0.5/0.05)
- vanish probe: 0/12 vs 2/6 baseline; live smoke green on PORT=3004

src/agent/subagents/visual-maker.ts

@@ -1,4 +1,5 @@
 import type { AssistantMessage, Message, Tool, ToolResultMessage, Usage } from "@earendil-works/pi-ai";
+import { normalizeContext } from "@earendil-works/pi-ai";
 import { Type } from "typebox";
 import { piEngineFor, type PiEngine, type ThinkingLevel } from "../models.ts";
 import type { VisualResult } from "../../core/contracts.ts";
@@ -307,7 +308,10 @@ async function streamOnce(
 	reasoning: ThinkingLevel | undefined,
 	abortSignal?: AbortSignal,
 ): Promise<AssistantMessage> {
-	const stream = engine.streamFn(engine.model, { systemPrompt, messages, tools }, {
+	// 0.87.1: provider-facing contexts are TranscriptContexts — the prompt
+	// and tool declarations fold into a leading system message.
+	// normalizeContext is the library's only Context→TranscriptContext entry.
+	const stream = engine.streamFn(engine.model, normalizeContext({ systemPrompt, messages, tools }), {
 		reasoning: reasoning && reasoning !== "off" ? reasoning : undefined,
 		apiKey: process.env.OPENROUTER_API_KEY || undefined,
 		signal: abortSignal,