perf: Add archived shell snapshot support

apps/server/src/checkpointing/Layers/CheckpointDiffQuery.test.ts

@@ -92,6 +92,8 @@ describe("CheckpointDiffQueryLive", () => {
             Effect.die("CheckpointDiffQuery should not request the full orchestration snapshot"),
           getShellSnapshot: () =>
             Effect.die("CheckpointDiffQuery should not request the orchestration shell snapshot"),
+          getArchivedShellSnapshot: () =>
+            Effect.die("CheckpointDiffQuery should not request archived shell snapshots"),
           getSnapshotSequence: () => Effect.succeed({ snapshotSequence: 0 }),
           getCounts: () => Effect.succeed({ projectCount: 0, threadCount: 0 }),
           getActiveProjectByWorkspaceRoot: () => Effect.succeed(Option.none()),
@@ -172,6 +174,8 @@ describe("CheckpointDiffQueryLive", () => {
             Effect.die("CheckpointDiffQuery should not request the full orchestration snapshot"),
           getShellSnapshot: () =>
             Effect.die("CheckpointDiffQuery should not request the orchestration shell snapshot"),
+          getArchivedShellSnapshot: () =>
+            Effect.die("CheckpointDiffQuery should not request archived shell snapshots"),
           getSnapshotSequence: () => Effect.succeed({ snapshotSequence: 0 }),
           getCounts: () => Effect.succeed({ projectCount: 0, threadCount: 0 }),
           getActiveProjectByWorkspaceRoot: () => Effect.succeed(Option.none()),
@@ -220,6 +224,8 @@ describe("CheckpointDiffQueryLive", () => {
             Effect.die("CheckpointDiffQuery should not request the full orchestration snapshot"),
           getShellSnapshot: () =>
             Effect.die("CheckpointDiffQuery should not request the orchestration shell snapshot"),
+          getArchivedShellSnapshot: () =>
+            Effect.die("CheckpointDiffQuery should not request archived shell snapshots"),
           getSnapshotSequence: () => Effect.succeed({ snapshotSequence: 0 }),
           getCounts: () => Effect.succeed({ projectCount: 0, threadCount: 0 }),
           getActiveProjectByWorkspaceRoot: () => Effect.succeed(Option.none()),

apps/server/src/orchestration/Layers/OrchestrationEngine.test.ts

@@ -8,7 +8,6 @@ import {
   TurnId,
   type OrchestrationEvent,
   ProviderInstanceId,
-  type OrchestrationReadModel,
 } from "@t3tools/contracts";
 import { Effect, Layer, ManagedRuntime, Metric, Option, Queue, Stream } from "effect";
 import { describe, expect, it } from "vitest";
@@ -178,6 +177,13 @@ describe("OrchestrationEngine", () => {
               threads: [],
               updatedAt: projectionSnapshot.updatedAt,
             }),
+          getArchivedShellSnapshot: () =>
+            Effect.succeed({
+              snapshotSequence: projectionSnapshot.snapshotSequence,
+              projects: [],
+              threads: [],
+              updatedAt: projectionSnapshot.updatedAt,
+            }),
           getSnapshotSequence: () =>
             Effect.succeed({ snapshotSequence: projectionSnapshot.snapshotSequence }),
           getCounts: () => Effect.succeed({ projectCount: 1, threadCount: 1 }),

apps/server/src/orchestration/Layers/ProjectionSnapshotQuery.test.ts

@@ -440,6 +440,126 @@ projectionSnapshotLayer("ProjectionSnapshotQuery", (it) => {
     }),
   );
 
+  it.effect("keeps archived threads out of the main shell snapshot", () =>
+    Effect.gen(function* () {
+      const snapshotQuery = yield* ProjectionSnapshotQuery;
+      const sql = yield* SqlClient.SqlClient;
+
+      yield* sql`DELETE FROM projection_projects`;
+      yield* sql`DELETE FROM projection_threads`;
+      yield* sql`DELETE FROM projection_state`;
+
+      yield* sql`
+        INSERT INTO projection_projects (
+          project_id,
+          title,
+          workspace_root,
+          default_model_selection_json,
+          scripts_json,
+          created_at,
+          updated_at,
+          deleted_at
+        )
+        VALUES (
+          'project-archive-test',
+          'Archive Test',
+          '/tmp/archive-test',
+          '{"provider":"codex","model":"gpt-5-codex"}',
+          '[]',
+          '2026-04-06T00:00:00.000Z',
+          '2026-04-06T00:00:01.000Z',
+          NULL
+        )
+      `;
+
+      yield* sql`
+        INSERT INTO projection_threads (
+          thread_id,
+          project_id,
+          title,
+          model_selection_json,
+          runtime_mode,
+          interaction_mode,
+          branch,
+          worktree_path,
+          latest_turn_id,
+          latest_user_message_at,
+          pending_approval_count,
+          pending_user_input_count,
+          has_actionable_proposed_plan,
+          created_at,
+          updated_at,
+          archived_at,
+          deleted_at
+        )
+        VALUES
+          (
+            'thread-active',
+            'project-archive-test',
+            'Active Thread',
+            '{"provider":"codex","model":"gpt-5-codex"}',
+            'full-access',
+            'default',
+            NULL,
+            NULL,
+            NULL,
+            NULL,
+            0,
+            0,
+            0,
+            '2026-04-06T00:00:02.000Z',
+            '2026-04-06T00:00:03.000Z',
+            NULL,
+            NULL
+          ),
+          (
+            'thread-archived',
+            'project-archive-test',
+            'Archived Thread',
+            '{"provider":"codex","model":"gpt-5-codex"}',
+            'full-access',
+            'default',
+            NULL,
+            NULL,
+            NULL,
+            NULL,
+            0,
+            0,
+            0,
+            '2026-04-06T00:00:04.000Z',
+            '2026-04-06T00:00:05.000Z',
+            '2026-04-06T00:00:06.000Z',
+            NULL
+          )
+      `;
+
+      yield* sql`
+        INSERT INTO projection_state (projector, last_applied_sequence, updated_at)
+        VALUES
+          (${ORCHESTRATION_PROJECTOR_NAMES.projects}, 4, '2026-04-06T00:00:07.000Z'),
+          (${ORCHESTRATION_PROJECTOR_NAMES.threads}, 4, '2026-04-06T00:00:07.000Z'),
+          (${ORCHESTRATION_PROJECTOR_NAMES.threadMessages}, 4, '2026-04-06T00:00:07.000Z'),
+          (${ORCHESTRATION_PROJECTOR_NAMES.threadProposedPlans}, 4, '2026-04-06T00:00:07.000Z'),
+          (${ORCHESTRATION_PROJECTOR_NAMES.threadActivities}, 4, '2026-04-06T00:00:07.000Z'),
+          (${ORCHESTRATION_PROJECTOR_NAMES.threadSessions}, 4, '2026-04-06T00:00:07.000Z'),
+          (${ORCHESTRATION_PROJECTOR_NAMES.checkpoints}, 4, '2026-04-06T00:00:07.000Z')
+      `;
+
+      const shellSnapshot = yield* snapshotQuery.getShellSnapshot();
+      assert.deepEqual(
+        shellSnapshot.threads.map((thread) => thread.id),
+        [ThreadId.make("thread-active")],
+      );
+
+      const archivedShellSnapshot = yield* snapshotQuery.getArchivedShellSnapshot();
+      assert.deepEqual(
+        archivedShellSnapshot.threads.map((thread) => thread.id),
+        [ThreadId.make("thread-archived")],
+      );
+      assert.equal(archivedShellSnapshot.threads[0]?.archivedAt, "2026-04-06T00:00:06.000Z");
+    }),
+  );
+
   it.effect(
     "reads targeted project, thread, and count queries without hydrating the full snapshot",
     () =>