Bump to v1.7.0: self-updater release-filtering fix

The client and the relay server are published from the same GitHub repo;
the server's releases use "server-" prefixed tags. RemSoundUpdater hit
/releases/latest, which is repo-wide — when a server release was newest,
the updater fed "server-v2.3" to ParseTag (-> a bogus 0.0.3) and concluded
"up to date", silently skipping real client updates.

CheckForUpdateAsync now lists /releases and picks the highest-versioned
release whose tag is a RemSound client tag (new IsClientReleaseTag: after
an optional leading "v", first char must be a digit). Drafts and
pre-releases are skipped. The server-side updater already filters to
"server-" tags, so client + server coexist in one repo cleanly.

Also rewrites build-release.ps1 with a data-safety check: it publishes to
a fresh staging folder and aborts the release if any logs/, profiles/,
recordings/ folder, .log file or remsound.config.json is present in the
staged output or the finished zip — preventing a repeat of the v1.5/v1.6
zips that shipped with developer logs and profiles.

No wire-format or audio-pipeline changes — v1.5/v1.6/v1.7 interoperate.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/RemSound.App/RemSound.App.csproj

@@ -14,7 +14,7 @@
          tag_name on the latest GitHub release; bump it on every public release. The
          AssemblyVersion / FileVersion default to this value, and Assembly.GetName().Version
          is what the About dialog and the updater both read. -->
-    <Version>1.6.0</Version>
+    <Version>1.7.0</Version>
   </PropertyGroup>
 
   <ItemGroup>