docs: complete XML doc comments via fixdocs (2757 to 131 findings)

Add missing <returns>/<param>/<summary>/<typeparam> tags and clean up
misused inheritdoc across 481 files so the documented API surface is
complete. Documentation-only (zero code lines changed). The 131 remaining
findings are inheritdoc-style warnings deliberately left to preserve
hand-written implementation rationale (plan-decision notes, race-condition
explanations).

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Browser.Tests/GalaxyBrowseSessionTests.cs

@@ -51,6 +51,7 @@ public sealed class GalaxyBrowseSessionTests
     /// <summary>Each session must publish a distinct <see cref="GalaxyBrowseSession.Token"/>
     /// so the AdminUI registry can disambiguate concurrent browse sessions against the
     /// same driver config.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task Token_is_unique_per_session()
     {
@@ -63,6 +64,7 @@ public sealed class GalaxyBrowseSessionTests
     /// <summary><see cref="GalaxyBrowseSession.LastUsedUtc"/> is primed to the
     /// construction time so the registry reaper has a sensible baseline before the
     /// first Root/Expand/Attributes call lands.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task LastUsedUtc_is_initialized_at_construction()
     {
@@ -79,6 +81,7 @@ public sealed class GalaxyBrowseSessionTests
     /// registry's reaper may race a client-initiated close, so the second call must
     /// no-op rather than throw <see cref="ObjectDisposedException"/> or hit the
     /// already-disposed gRPC channel.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task DisposeAsync_is_idempotent()
     {
@@ -91,6 +94,7 @@ public sealed class GalaxyBrowseSessionTests
     /// <summary>After disposal, any <see cref="GalaxyBrowseSession.ExpandAsync"/> call
     /// must surface <see cref="ObjectDisposedException"/> — not a downstream channel
     /// fault — so the AdminUI sees a clean "session closed" signal.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ExpandAsync_after_dispose_throws_ObjectDisposedException()
     {
@@ -104,6 +108,7 @@ public sealed class GalaxyBrowseSessionTests
     /// hasn't been seen by a prior Root/Expand call — the cache is the source of
     /// truth, and silently returning [] would mask AdminUI bugs that browse with a
     /// stale path.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ExpandAsync_unknown_tag_throws_ArgumentException()
     {

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Browser.Tests/GalaxyDriverBrowserTests.cs

@@ -23,6 +23,7 @@ public sealed class GalaxyDriverBrowserTests
 
     /// <summary>An empty Gateway.Endpoint must fail fast with a clear, endpoint-mentioning
     /// message rather than surfacing a downstream gRPC URI parse error.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task OpenAsync_with_empty_endpoint_throws_InvalidOperationException()
     {
@@ -34,6 +35,7 @@ public sealed class GalaxyDriverBrowserTests
 
     /// <summary>An empty MxAccess.ClientName must fail fast — refused so the gateway
     /// side doesn't see anonymous browse sessions during triage.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task OpenAsync_with_empty_clientName_throws_InvalidOperationException()
     {
@@ -45,6 +47,7 @@ public sealed class GalaxyDriverBrowserTests
 
     /// <summary>A JSON literal that deserializes to null must fail fast with a
     /// "deserialized to null" message — never a downstream NRE.</summary>
+    /// <returns>A task that represents the asynchronous test operation.</returns>
     [Fact]
     public async Task OpenAsync_with_null_json_throws_InvalidOperationException()
     {