chore(release): close the v1.11.0 cycle

Version to 1.11.0 in the csproj, changelog and roadmap entries for the local
state. Not published: the public release stays at v1.5.6 and the download links
are untouched.

repo.json goes back to 1.5.6.0. It had been carrying the development version
while all three download links pointed at the v1.5.6 archive, which is a trap
waiting for a merge: Dalamud would offer an update to a version the download
does not contain, install v1.5.6 again, and offer the same update on the next
launch. main is unaffected -- it only ever saw 1.5.6.0 -- but the feature
branches have been inheriting the mismatch since v1.6.0.

The manifest version belongs to what the links actually serve. A local state is
tracked by the csproj and the changelog, which is what they are for.

Testing channel deliberately not opened yet. Publishing 1.11.0 as a test build
would ship a modern settings window alongside a first-run wizard and a message
list that are still stock ImGui -- and 1.10.0 would ship the pinned-tell-history
bug that 1.11.0 fixes.

HellionChat/HellionChat.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Dalamud.NET.Sdk/15.0.0">
     <PropertyGroup>
         <!-- Independent versioning; see yaml changelog for upstream Chat 2 base -->
-        <Version>1.10.0</Version>
+        <Version>1.11.0</Version>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
         <!-- Use lock file to pin exact versions -->