Task: Model the hand-written tables that have a codegen shape

Every table a codegen shape covers has a model, so its schema, drop, notify trigger and C++ come from one source.

• Each of the 23 tables with no model is either modelled, with generated SQL identical to the current file or the difference explained, or recorded as staying hand-written with its reason.
• The census reports the modelled tables as codegen output.

(Implementation strategy. Written when work starts; key decisions are distilled into the parent story's * Decisions at close, but the plan itself stays — it is the historical record of what we did.)

Every number this task claims about a tree, with the command that produced it and the commit it was measured at. A number without both is not a measurement, because a clean-up record describes a tree and trunk moves under a branch: a consumer count, a gate's component count and a suite's size all change with no code changing, and the reader of a bare number cannot tell which tree it came from. Where the raw output matters, put it in an evidence/ file beside the task and name that file in the Command column.

From the hand-written SQL census in Find why so much SQL is hand-written and generate what codegen can.

The 25 tables: 18 with no model (junctions such as iam_account_roles, iam_role_permissions, reporting_risk_report_config_books and _portfolios; time series such as iam_auth_events, iam_session_samples and the telemetry samples; DQ publication logs; compute_batch_dependencies, scheduler_job_instances, workspace_trade_scope and others) and 7 DQ artefact staging tables. mq and telemetry are infrastructure and likely stay hand-written; mq_messages holds the only hard REFERENCES in the tree.

Manual QA scenarios (scaffolded via compass add test_scenario) that verify this task. Link new ones here as they're created; the scenario doc itself links back via its "Verifies task" field.