chore(vendor): import pi 1.3.0

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: 71023aec1546d6d677a65669c5665c0927ce0dd0

third_party/pi/packages/durable/src/entries.ts

@@ -0,0 +1,34 @@
+import type { JsonValue } from "@earendil-works/chord";
+import type { CompactionReason, ToolDiagnostic } from "./harness/types.ts";
+import type { Entry, EntryRecord, TypedEntry } from "./types.ts";
+
+/** Define a typed entry kind whose `is()` guard narrows by `EntryRecord.kind`. */
+export function defineEntry<D extends JsonValue = never>(kind: string): Entry<D> {
+	if (typeof kind !== "string" || kind.length === 0) throw new TypeError("Entry kind must be a non-empty string");
+	return {
+		kind,
+		is: (entry: EntryRecord | undefined): entry is TypedEntry<D> => entry !== undefined && entry.kind === kind,
+	};
+}
+
+/** User input: `model` is `[UserMessage]`. Written by submissions. */
+export const UserEntry = defineEntry("pi.user");
+/** Provider result with any stop reason: `model` is `[AssistantMessage]`. Written by generation. */
+export const AssistantEntry = defineEntry("pi.assistant");
+/** Positional prompt and tool change: `model` is `[SystemMessage]` with empty `content`. */
+export const SystemEntry = defineEntry("pi.system");
+/**
+ * Tool result: `model` is `[ToolResultMessage]`, whose content ends with the rendered diagnostics block; `data` holds
+ * the structured diagnostics, possibly none. Written by tool tasks, and by generation for calls it did not offer.
+ */
+export const ToolResultEntry = defineEntry<{ diagnostics: ToolDiagnostic[] }>("pi.tool-result");
+/**
+ * Start of a new context: always `head: "self"`, with `model` absent for a plain reset or `[UserMessage]` carrying the
+ * handoff text. Written by `Conversation.reset()` and the `handoff` tool control.
+ */
+export const ResetEntry = defineEntry("pi.reset");
+/**
+ * Compaction summary: `model` is `[UserMessage]` with the wrapped summary, `head` the first kept entry. Written by
+ * compaction tasks, directly or through a write submission.
+ */
+export const CompactionEntry = defineEntry<{ reason: CompactionReason }>("pi.compaction");