Container logs carry a level, and a workload's Logs tab opens on its own lines

Two changes to logs, both on main for the next release: a line tailed from a pod's stdout now carries a severity, and a workload's Logs tab on the mesh screen starts from the workload's own lines.

• Container logs carry a level. A line read from a pod's stdout arrives with no OTLP severity, so the Logs screen showed "—" for it, the "INFO+" floor hid it, and an ERROR line from a plain-stdout app never became an error issue. The node agent now reads the level off the line — a JSON level / severity / lvl field, named or pino's numeric 30/50; a level=warn key=value pair; or the usual upper-case token (… DEBUG [main] …, [INFO], ERROR:) — and sets the OTel severity number and text. Records that already carry a level are left alone. On by default, off with sensor.agent.logs.parseSeverity=false. Rows ingested before the upgrade keep their empty level until they age out. See what your service should emit.

• A workload's Logs tab opens on its own lines. On the mesh screen, the three sources of a workload's logs were buttons, all on at once, and the first was labelled app. They are now checkboxes: the first carries the workload's name and is the only one checked by default; ztunnel's and the waypoint's lines are about the workload, not by it, and are a click away. One source always stays on, and the choice travels in the URL as before.