kit + server component improvements

you can use --server-components with bun build, and you get a slightly
more correct output. this output is not yet perfect or usable. but i am
committing this as a checkpoint as the next step is a large design
change for how `kit.DevServer` bundles and re-bundles files

we are removing the old `Framework` struct, and replacing it with a new
one with a similar purpose: configuration options targeted towards
framework developers. it tells the bundler how to glue the framework to
the application, mostly in regards to react server components

introduce `bundle_v2.AstBuilder`, which is used for parallel generation
of virtual modules. previously, this used a string builder combined with
the javascript parser. this is silly and will not be fun to use for the
3-5 file kinds that the bundler will have to generate. this builder
makes it very easy

introduce `kit.DevServer.IncrementalGraph`, which will keep track of
changes between bundle tasks. however, this code is not ripe and will
be iterated on extensively. i don't think it's approach is sound yet

build.zig

@@ -157,7 +157,7 @@ pub fn build(b: *Build) !void {
 
     // TODO: Upgrade path for 0.14.0
     // b.graph.zig_lib_directory = brk: {
-    //     const sub_path = "src/deps/zig/lib";
+    //     const sub_path = "vendor/zig/lib";
     //     const dir = try b.build_root.handle.openDir(sub_path, .{});
     //     break :brk .{ .handle = dir, .path = try b.build_root.join(b.graph.arena, &.{sub_path}) };
     // };
@@ -295,7 +295,7 @@ pub fn build(b: *Build) !void {
         bun_check_obj.generated_bin = null;
         step.dependOn(&bun_check_obj.step);
 
-        // The default install step will run zig build check This is so ZLS
+        // The default install step will run zig build check. This is so ZLS
         // identifies the codebase, as well as performs checking if build on
         // save is enabled.