Keep a FOS report readable after its task is gone

[mastacontrola]

Port of 1.6's schema 341 (#1236). Writer half only — this branch has no Task Management log pane, so there is no reader to change, which is also what makes the defect worse here rather than milder.

The problem

taskLog stores no host and no task type of its own and reaches both through tasks. Nothing deletes taskLog rows — but Host::destroy() calls TaskManager->destroy() and taskLog is in no cascade at all. So deleting a host destroys its tasks and leaves the reports behind with nothing to join to, losing the host name at the same moment the host row that could have supplied it goes.

On 1.6 the log pane at least still shows the text with a blank host column. Here tasklog is in Route::$validClasses and the REST API is its only reader — it hands back a report whose taskID points at nothing and no way at all to learn which machine it came from.

The fix

Schema 283 adds logHostID, logHostName, logTaskTypeName and backfills the reports whose task is still there, so the history is not split between rows that can answer the question and rows that cannot. TaskError fills them; nothing else does.

Every other row in this table is a state transition written by TaskingElement::taskLog() on every transition — meaningless without its task anyway, so it leaves them empty. Same reasoning that gave logText no value on a state row in step 280.

The state a row records was never at risk: taskLog stores taskStateID itself, so that lookup survives its task.

Two column shapes, following what the writer can actually produce: save() omits an unset optional column whose key ends in id, so logHostID lands NULL, but writes '' for every other unset field — the trap step 282 had to repair for logType.

Why not block deleting a task that has reports: it inverts the dependency — a diagnostic artifact would constrain operational cleanup — and to be consistent it would have to block host deletion too, since that's the path that actually removes tasks.

Not ported

The manifest repair that was the other half of #1236. This branch has no schema-expected.php, no SchemaReconciler and no bin/schema-manifest.php, so there is no second description of taskLog to drift out of step.

Tests

tests/task-error-report.test.php gains four checks in its own source-level idiom: the writer stores each field, the schema step adds the columns, and it backfills. Mutation-verified — dropping the three set() calls, dropping a field from the model, misspelling a column in the ALTER, and removing the backfill each fail it.

Step 283 was executed against a 1.5 server over temporary shadow tables and produces the intended rows: report with a live task filled, report already orphaned left empty, state row untouched.

sh tests/run-all.sh — 19 passed, 0 failed.

Downstream

No route classes changed, so no FogApi sync is implied.