[mrcsin]

Problem

The status bar's archive indicator and its ConnectionLost entry came from the live-edge poll, which a
later slice of the OPC UA live edge (#116) replaces. The poll turned any failure, a missing trends table
included, into ConnectionLost. One outage also made two panel entries: the read loop's third-failure
report and the status bar's fault report. The catalogue read inherited the 300 s connection backstop, so
a stalled server would have taken about 15 minutes to raise a fault through it.

What changed

• PenCatalogueSync publishes ArchiveConnectionState through a sink of ArchiveReadLoop; MarkerSync
  passes none. ConnectionLost after three connection-class failures in a row, Connected on the first
  success and on the first success after a fault. One outage makes one entry from the loops and the bar.
• Connection class is ArchiveFault.Unreachable. ArchiveExceptionMapper widens it to SQLSTATE class
  08, 57P01-57P03 and 53300; 57014 stays QueryTimedOut. The Unreachable texts in both resx
  files widen to match.
• The catalogue command has its own 5 s CommandTimeout. The window reads the catalogue at open.
• IDataProvider.ConnectionFaults, TrendCoordinator.ConnectionFaults and the poll's state machine are
  deleted. The poll keeps its statements, samples, 10 s tick bound and failure warning.
• Docs: data-integration.md (section renamed to "The connection state the catalogue read reports",
  residual cases under "No failure stops at the log"), overview.md, charting.md,
  trend-interaction.md, testing-strategy.md, AGENTS.md.

Known residual until the poll is deleted in a later slice of this roadmap: a non-connection poll failure
reaches the panel only through the minimap's band reads or the next history read. The list is in
data-integration.md#no-failure-stops-at-the-log.

How it was verified

• dotnet build SemiPlot.slnx: 0 errors.
• dotnet format SemiPlot.slnx --verify-no-changes: exit 0; dotnet terse over the 40 touched .cs files:
  exit 0.
• SemiPlot.Tests.Unit: 2297/2297. SemiPlot.Tests.Integration: 196/196.
• TrendWindowTests.ThreeUnreachableCatalogueReads_TurnTheBarToFault_WithOneConnectionLostEntry and
  TheWindowReadsTheCatalogueAtOnce were red before the wiring change.
• Not run: the manual outage check on the demo stand (stop, start and pause the bench container). The
  automated suites stand in for it in this unattended roadmap run.
• PenEditorViewTests.ANameTypedWhileARefreshRuns_ReachesNoFieldAndWritesNothing failed once and then
  passed 5/5; it is outside this change.

Per-task commits before collapse

fb89170 docs(plans): correct the verify list
dee54aa docs(plans): record the exec run and checks
83301f5 fix(comments): address audit findings
913c178 fix(tests): address review findings
84aafa5 fix(bridge): address review findings
0fca00d docs(architecture): describe the catalogue state
93656a2 docs(plans): record the acceptance checks
1de694f refactor(data): delete the poll's connection state
ea5a25c feat(ui): feed the status bar from the catalogue
338820a test(data): arm the realtime tests on poll log lines
82f0cb7 feat(data): bound the catalogue read, widen Unreachable
2053abf feat(bridge): raise the archive state from the catalogue