Reopen durable sessions

Outcome: complete a run, release the first Runtime, reopen the same database, and read the original run, two messages, and twelve ordered events.

Module: examples.durable_agent

python examples/durable_agent.py

create_application(database_path) returns an Application and SQLitePersistence for explicit Runtime composition. Expected status is completed with one session/run, two messages, and twelve events.

Muru Workspace hydrates the snapshot then follows new events after its last sequence. A restart during nonterminal work produces process_interrupted; it does not resume Python coroutines. Lock exhaustion surfaces as storage_busy.

Qualified by tests/qualification/test_scenarios.py::test_durable_scenario_restores_history_from_same_file, SQLite Runtime tests, HTTP/WebSocket reopen tests, and the Chromium restart flow.