fix(mtconnect): the Agent refuses count ABOVE bufferSize, not at it (#825)

Live gate against the cppagent 2.7 fixture: count=16384 with bufferSize
16384 streams; 16385 is OUT_OF_RANGE ('count' must be less than 16385).
Warn only when SampleCount > bufferSize, pin both sides of the edge
against the live Agent, and correct the #804 wording that said 'at or
above'.

docs/drivers/MTConnect.md

@@ -362,7 +362,7 @@ what the driver's cursor expects) is detected **two ways**, both triggering a
 **Re-baselines without progress are bounded *and visible* (#804).** The reconnect
 backoff already paced a stream that only ever re-baselines (`A_rebaseline_that_delivers_nothing…`),
 but every `/current` also marked the stream delivered, so the driver read **Healthy**
-for ever while no `/sample` chunk arrived — the live case is a `SampleCount` at or
+for ever while no `/sample` chunk arrived — the live case is a `SampleCount`
 above the Agent's `bufferSize`, refused `OUT_OF_RANGE` (`'count' must be less than N`)
 on every open. After **3** consecutive re-baselines with no chunk in between
 (`MaxRebaselinesWithoutProgress`, the Java driver's `MAX_REBASELINES_WITHOUT_PROGRESS`)
@@ -371,11 +371,12 @@ observations in between"` and one Warning naming the `bufferSize` cause; it stay
 Degraded across further re-baselines until a chunk is delivered. Values keep flowing
 off the re-baselines and `LastSuccessfulRead` keeps advancing — each `/current` is the
 Agent answering — so the comms-loss watchdog does not reconnect-loop a configuration
-problem. Size `SampleCount` below the Agent's `bufferSize` (in the `/probe` header).
+problem. Size `SampleCount` at most the Agent's `bufferSize` (in the `/probe` header).
 **It is caught before it happens (#825):** the `/probe` header's `bufferSize` is parsed
 (`MTConnectProbeModel.BufferSize`, advisory — missing/malformed is null, never a parse failure); **Test
 Connect** reads `sampleCount` (default 1000 when absent) and answers Ok **with a warning** (an amber
-"OK with warning" chip showing the text) when it is at or above the buffer, and the driver's **initialize**
+"OK with warning" chip showing the text) when it is **above** the buffer (live, cppagent 2.7: `count == bufferSize` is
+accepted, `bufferSize + 1` refused `'count' must be less than {bufferSize+1}`), and the driver's **initialize**
 (every deploy) logs the same Warning and puts `agentBufferSize` on the `/hosts` diagnostics bag.
 
 **An Agent `instanceId` change means the Agent restarted**, and is checked