Syntax styling is no problem, this is already supported. Code completion is unlikely to happen in the near future, as are all other things.
The build system is designed with compiler languages in mind, an interpreted language doesn't fit in well. What could be done is to run your scripts in something like the Code::Blocks script console, but then it would have the Code::Blocks bindings, not your application's bindings. So basically, since Squirrel's main feature is being an embedded language with native bindings (which you obviously want to use), there's not much Code::Blocks can do but simply launch your program as usual (and this incidentially runs Squirrel, without Code::Blocks knowing).
What could be done, however, is a remote debugger plugin for Squirrel. However, again, this is not going to happen in the near future, as it needs an entirely different approach from the present gdb-based one (and probably we'd have to run two debuggers in parallel, then...?).
