Align docs with StyleGuide and add CLAUDE.md

- Rename 16 kebab-case docs to PascalCase per StyleGuide
- Move per-language client design docs from docs/ to clients/<lang>/
  alongside their READMEs
- Add ## Related Documentation sections to 15 docs that lacked one
- Fix sentence-case violations in H3 headings (StyleGuide rule)
- Update cross-references in gateway.md, client READMEs, scripts,
  and generate-proto.ps1 helpers to follow the new paths
- Add CLAUDE.md with build/test commands, the source-update
  verification matrix, the parity-first contract, and pointers
  to MXAccess and Galaxy Repository analysis sources

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/Metrics.md

@@ -64,7 +64,7 @@ _eventStreamSendLatencyHistogram = _meter.CreateHistogram<double>("mxgateway.eve
 | `mxgateway.commands.duration` | `method`, optional `category` | Command round-trip time. The `category` tag is added on failure so success and failure latencies stay distinguishable. |
 | `mxgateway.events.stream_send.duration` | `family` | Time spent writing each public event to the gRPC response stream in `MxAccessGatewayService.StreamEvents`. |
 
-### Observable Gauges
+### Observable gauges
 
 Observable gauges are pull-based; the `Meter` invokes the supplied callback whenever a listener samples it. Each callback re-acquires `_syncRoot` so the gauge value matches the snapshot taken at the same instant.
 
@@ -201,10 +201,10 @@ metrics.RecordEventStreamSend(publicEvent.Family.ToString(), stopwatch.Elapsed);
 
 ## Dashboard Consumption
 
-`Dashboard/DashboardSnapshotService.cs` calls `_metrics.GetSnapshot()` once per `GetSnapshot` invocation and projects it into the dashboard transport types together with the session registry view. The dashboard receives a single, internally consistent snapshot per tick rather than reading individual counters at separate times. See [Gateway Dashboard Design](./gateway-dashboard-design.md) and [Dashboard Interface Design](./DashboardInterfaceDesign.md) for the projection rules and wire format.
+`Dashboard/DashboardSnapshotService.cs` calls `_metrics.GetSnapshot()` once per `GetSnapshot` invocation and projects it into the dashboard transport types together with the session registry view. The dashboard receives a single, internally consistent snapshot per tick rather than reading individual counters at separate times. See [Gateway Dashboard Design](./GatewayDashboardDesign.md) and [Dashboard Interface Design](./DashboardInterfaceDesign.md) for the projection rules and wire format.
 
 ## Related Documentation
 
-- [Gateway Dashboard Design](./gateway-dashboard-design.md)
+- [Gateway Dashboard Design](./GatewayDashboardDesign.md)
 - [Dashboard Interface Design](./DashboardInterfaceDesign.md)
 - [Sessions](./Sessions.md)