mbproxy: strip historical phase/wave/plan references from source comments

Comments described the *history* of how the code arrived (phase numbers,
wave IDs, review IDs, dated TODOs) instead of what it does today. That
scaffolding rotted as the codebase evolved. Cleaned 60 source files +
.gitignore; behaviour unchanged (387/387 tests still pass).

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

mbproxy/src/Mbproxy/Admin/StatusSnapshotBuilder.cs

@@ -66,10 +66,6 @@ internal sealed class StatusSnapshotBuilder
             var activeUpstreams = supervisor?.ActiveUpstreams ?? Array.Empty<UpstreamPipe>();
             var clientSnapshots = activeUpstreams
                 .Select(p => new ClientSnapshot(
-                    // Phase 12 (W3 cleanup) — the second `?.Address.ToString()` was
-                    // unreachable: if RemoteEp is non-null the first ?.ToString() returns
-                    // a string; if it's null the second branch's outer `?.` short-circuits
-                    // identically. Simplified to the equivalent two-branch form.
                     Remote:         p.RemoteEp?.ToString() ?? "?",
                     ConnectedAtUtc: p.ConnectedAtUtc,
                     PdusForwarded:  p.PdusForwardedCount))
@@ -114,7 +110,6 @@ internal sealed class StatusSnapshotBuilder
                             CacheBytes:                0,
                             ResponseDropForFullUpstream: 0);
 
-            // Phase 08: ConnectsSuccess / ConnectsFailed are now tracked in ProxyCounters.
             long connectsSuccess = counters.ConnectsSuccess;
             long connectsFailed  = counters.ConnectsFailed;