feat(tasks): add durable Pi task sessions

.semgrep/rules/security/idor-team-scoped-models.yaml

@@ -289,6 +289,7 @@ rules:
                               |TaskAutomation
                               |TaskPresence
                               |TaskRun
+                              |TaskSession
                               |TaskThreadMessage
                               |TaskThreadMessageMention
                               |Channel
@@ -606,6 +607,7 @@ rules:
                         |TaskAutomation
                         |TaskPresence
                         |TaskRun
+                        |TaskSession
                         |TaskThreadMessage
                         |TaskThreadMessageMention
                         |Channel

posthog/test/setup_receivers_baseline.txt

@@ -91,6 +91,7 @@ post_delete:products.feature_flags.backend.local_evaluation.feature_flag_changed
 post_delete:products.feature_flags.backend.models.feature_flag.refresh_flag_cache_on_updates
 post_delete:products.slack_app.backend.signals.invalidate_repo_list_on_user_github_change
 post_delete:products.surveys.backend.models.survey_changed
+post_delete:products.tasks.backend.models.delete_task_session_object
 post_delete:products.workflows.backend.models.hog_flow.hog_flow.hog_flow_deleted
 post_init:posthog.storage.gateway_credential_signal_handlers._snapshot_oauth
 post_init:posthog.storage.gateway_credential_signal_handlers._snapshot_secret_key

products/tasks/backend/constants.py

@@ -8,6 +8,7 @@
 MODAL_VM_SANDBOX_FEATURE_FLAG = "tasks-modal-vm-sandbox"
 MODAL_NETWORK_ALLOWLIST_FEATURE_FLAG = "tasks-modal-network-allowlist"
 AGENT_RUN_OTEL_TELEMETRY_FEATURE_FLAG = "tasks-agent-run-otel-telemetry"
+PI_CLOUD_RUNTIME_FEATURE_FLAG = "pi-harness"
 # Run-state key the telemetry flag decision is stamped under at dispatch (temporal/client.py).
 # Consumers read the stamp, so the decision stays stable for the run's whole lifetime.
 AGENT_OTEL_TELEMETRY_STATE_KEY = "agent_otel_telemetry_enabled"
@@ -66,6 +67,8 @@ def vm_sandbox_allowed_origins(*, distinct_id: str, organization_id: str) -> set
 
 MAX_CUSTOM_IMAGES_PER_TEAM = 20
 MAX_CUSTOM_IMAGES_PER_USER = 10
+TASK_SESSION_MAX_SIZE_BYTES = 10 * 1024 * 1024
+TASK_SESSION_UPLOAD_FORM_OVERHEAD_BYTES = 64 * 1024
 
 MODAL_DIRECTORY_RESUME_SNAPSHOTS_FEATURE_FLAG = "tasks-modal-directory-resume-snapshots"
 STREAM_VIA_PROXY_FEATURE_FLAG = "tasks-stream-via-proxy"