fix: show native Claude CLI usage as unpriced

src/core/contracts/claude-code.ts

@@ -1,3 +1,5 @@
+export const CLAUDE_CODE_PROVIDER = "claude-code";
+
 /** Installation/version only. Never an authentication, quota, or billing verdict. */
 export interface ClaudeCodeStatus {
 	state: "not-found" | "meets-minimum" | "update-required" | "version-unchecked";

src/core/contracts/models.ts

@@ -21,7 +21,8 @@ export interface ModelCatalogEntry {
 	 * thinkingLevelMap — e.g. GLM-5.3-flash: low|high|max). The thinking
 	 * picker lists exactly these; anything else is a lie. */
 	supportedLevels: ThinkingLevel[];
-	cost: { input: number; output: number; cacheRead: number; cacheWrite: number };
+	/** Null when LearnHarness cannot estimate prices for this connection. */
+	cost: { input: number; output: number; cacheRead: number; cacheWrite: number } | null;
 	contextWindow: number;
 	maxTokens: number;
 }