feat: adapt to DSH 0.1.2-alpha.5 and bump to v0.19.0-alpha.0

- pins: CI mount-gate CLI, dsh.plugin.json engines floor, and the
  @deepseek-ai/* peer floor / devDependencies baseline move to
  0.1.2-alpha.5 (dsh-client-locale trails at 0.1.2-alpha.3 — no such
  release upstream; ^0.1.2-alpha.3 already accepts the alpha.5 runtime)
- code: migrate the alpha.4 Session.events removal to snapshotEvents()
  (sidechat transcript live reads, fork inheritance, jobs.output replay,
  subagent activity) and drop the seedLength meta field the host removed
  from CreateAgentOptions.meta
- gates: pnpm peers check clean, typecheck + 1137 unit tests green,
  real-host mount smoke 14/14 on npm-published 0.1.2-alpha.5

src/client/service.ts

@@ -472,7 +472,7 @@ export function matchUrlTarget(tabs: readonly TabDescriptor[], url: URL): TabDes
  * The plugin version this service instance reports. Keep in lockstep with
  * `package.json`'s version — `tests/service.spec.ts` asserts the pair.
  */
-export const SIDEBAR_SERVICE_VERSION = '0.18.1-alpha.0'
+export const SIDEBAR_SERVICE_VERSION = '0.19.0-alpha.0'
 
 /**
  * Monotonic capability list consumers use to gate new API usage (features

src/context-types.ts

@@ -87,11 +87,12 @@ export interface SidebarSessionStore {
   get(id: string): {
     header: SidebarSessionHeader
     /**
-     * The live session's append-only event log (immutable snapshot; absent
-     * on sessions the runtime has not hydrated). Read-only access — the
-     * jobs.output route replays `job_output` tool/result rows from it.
+     * The live session's append-only event log as an immutable snapshot.
+     * Read-only access — the jobs.output route replays `job_output`
+     * tool/result rows from it. (The `Session.events` property this face
+     * mirrored was renamed to `snapshotEvents()` in DSH 0.1.2-alpha.4.)
      */
-    events?: readonly SidebarSessionEvent[]
+    snapshotEvents(): readonly SidebarSessionEvent[]
   } | undefined
 }
 

src/index.ts

@@ -473,7 +473,7 @@ function buildApi(
       // log opens on a tool event (subagent seeds do) carries seq 0, which a
       // literal `> 0` comparison would drop, so the absent case floors at -1.
       const afterSeq = rawAfter ?? -1
-      let events: readonly SidebarSessionEvent[] | undefined = ctx.sessions.get(sessionId)?.events
+      let events: readonly SidebarSessionEvent[] | undefined = ctx.sessions.get(sessionId)?.snapshotEvents()
       if (events === undefined) {
         const persistence = ctx.get('sessionPersistence')
         if (persistence !== undefined) {

src/jobs-routes.ts

@@ -211,7 +211,7 @@ export function buildJobsApi(ctx: Context, outputLimit: number): SidebarJobsRout
       // Merge the store's event log (durable seed + whatever it received)
       // with the live mirror, deduped by seq — a trace never double-counts.
       const bySeq = new Map<number, JobOutputTrace>()
-      for (const event of ctx.sessions.get(sessionId)?.events ?? []) {
+      for (const event of ctx.sessions.get(sessionId)?.snapshotEvents() ?? []) {
         const trace = traceOf(event)
         if (trace !== undefined) bySeq.set(trace.seq, trace)
       }

src/sidechat-routes.ts

@@ -168,15 +168,17 @@ function liveThreadAgent(ctx: Context, childId: string): Agent | undefined {
  * agent's in-memory log while the thread is attached — the freshest read,
  * including events not yet flushed — else the persisted logical log. Both
  * DSH generations expose these seams with the same shape (the 0.1.2
- * persistence layer packs chunk rows on disk but expands them on inspect),
- * which is why the transcript reads here instead of the client's
- * session-history RPC: that face (`ctx.connection.api`) was removed in
- * 0.1.2-alpha.1's Remote-gateway migration.
+ * persistence layer packs chunk rows on disk but expands them on inspect;
+ * the live log is `Session.snapshotEvents()`, the 0.1.2-alpha.4 rename of
+ * the `Session.events` property), which is why the transcript reads here
+ * instead of the client's session-history RPC: that face
+ * (`ctx.connection.api`) was removed in 0.1.2-alpha.1's Remote-gateway
+ * migration.
  */
 async function threadLogEvents(ctx: Context, childId: string): Promise<readonly SidechatLogEvent[]> {
   const agent = liveThreadAgent(ctx, childId)
   if (agent !== undefined) {
-    return agent.session.events as unknown as readonly SidechatLogEvent[]
+    return agent.session.snapshotEvents() as unknown as readonly SidechatLogEvent[]
   }
   const persistence = ctx.get('sessionPersistence') as SidebarSessionPersistenceService | undefined
   if (persistence === undefined) {
@@ -209,11 +211,11 @@ export function buildSidechatApi(ctx: Context): SidechatRoutes {
       }
       const parentSession = parent.session
       const inheritance = buildSidechatInheritance(
-        parentSession.events as unknown as readonly SidechatLogEvent[],
+        parentSession.snapshotEvents() as unknown as readonly SidechatLogEvent[],
       )
       const { agentPreset, setup } = await composeChildSetup(
         ctx,
-        resolvePresetId(parentSession.header, parentSession.events),
+        resolvePresetId(parentSession.header, parentSession.snapshotEvents()),
       )
       const childId = `session-${randomUUID()}` as SessionId
       const label = question === '' ? SIDE_NEW_THREAD_TITLE : sideLabel(question)
@@ -241,7 +243,6 @@ export function buildSidechatApi(ctx: Context): SidechatRoutes {
         meta: {
           ...(parentSession.header.cwd === undefined ? {} : { cwd: parentSession.header.cwd }),
           parentSession: parentSession.id,
-          seedLength: seed.length,
           origin: 'subagent',
           delegationDepth: (parentSession.header.delegationDepth ?? 0) + 1,
           ...(agentPreset === undefined ? {} : { agentPreset }),
@@ -310,7 +311,7 @@ export function buildSidechatApi(ctx: Context): SidechatRoutes {
           throw new SidebarError('sidechat-error', `thread resume failed: ${error instanceof Error ? error.message : String(error)}`, 500)
         }
       }
-      if (boundaryDelivered(agent.session.events as unknown as readonly SidechatLogEvent[])) {
+      if (boundaryDelivered(agent.session.snapshotEvents() as unknown as readonly SidechatLogEvent[])) {
         admitFollowup(agent, textPrompt(text))
       } else {
         // First message of an immediately-created thread: it carries the

src/subagent-live-route.ts

@@ -77,7 +77,7 @@ export function buildSubagentLiveApi(ctx: Context): SidebarSubagentLiveRoutes {
         if (entry.label?.startsWith(SIDE_LABEL_PREFIX) ?? false) continue
         try {
           const activity = lastActivity(
-            ctx.sessions.get(entry.id)?.events ?? [],
+            ctx.sessions.get(entry.id)?.snapshotEvents() ?? [],
             LIVE_WINDOW_MESSAGES,
           )
           if (activity.text !== undefined || activity.tool !== undefined) {