Merge pinned master into status bar token metrics

packages/core/session/src/index.ts

@@ -414,7 +414,9 @@ export class Session {
    * start here. Distinct from `header.seedLength`, the DURABLE fork-lineage
    * boundary: a resumed session's constructor seed is its full stored log,
    * while its header keeps the original fork value — this field is the
-   * in-process construction fact.
+   * in-process construction fact. An explicitly supplied empty seed has the
+   * same value as no seed (0); its `session/end-seed` event preserves the
+   * lifecycle distinction.
    *
    * Not persisted itself: a seeded session projects it into the log as the
    * `session/end-seed` event, which is what a consumer reading STORED history
@@ -430,7 +432,7 @@ export class Session {
   readonly firstLiveSeq: number
 
   constructor(id: SessionId, seed?: readonly SessionEvent[], header?: SessionHeader) {
-    if (seed) {
+    if (seed !== undefined) {
       // Validate the seed to the SAME invariants `append` enforces, so a
       // replay/fork (`ctx.sessions.create(id, { seed })`) cannot construct a
       // live log that no persistence backend could store: each event's `data`
@@ -467,7 +469,7 @@ export class Session {
     // captures the creation seed: no load-time write. Re-marking is skipped
     // because a cold session is resumed on first touch, so repeatedly opening
     // one must not grow its log per open.
-    if (this.firstLiveSeq > 0 && this.log.at(-1)?.type !== 'session/end-seed') {
+    if (seed !== undefined && this.log.at(-1)?.type !== 'session/end-seed') {
       this.append('session/end-seed', {})
     }
   }

packages/core/session/src/types.ts

@@ -280,7 +280,9 @@ export interface SessionEventMap {
   /**
    * Marks the end of a constructor seed. Events before it have smaller seq
    * values and came from the seed (resume, fork, or replay); this lifecycle
-   * produced none of them. This log-only event is the durable projection of
+   * produced none of them. An explicitly supplied empty seed puts the marker
+   * at seq 0, distinguishing an empty resumed session from a fresh session.
+   * This log-only event is the durable projection of
    * {@link Session.firstLiveSeq}. Its payload is empty — position and `time`
    * carry the meaning.
    *