feat(content): routing to provided .blog paths

This is a starting point to dynamically loading `markdown` files as blog
entries. With this change the *doc/about.md* and *doc/blog.md* files
are no longer builded into the executable and instead read from the
filesystem during runtime (along with the new test file *doc/test.md*).

src/main.zig

@@ -7,8 +7,11 @@ pub fn main() !void {
     const allocator = gpa.allocator();
 
     var app: App = .init(.{
-        .document = .init(@embedFile("blog")),
+        .page = .about,
+        .document = .init(try std.fs.cwd().readFileAlloc("./doc/about.md", allocator, .unlimited)),
     });
+    defer app.model.deinit(allocator);
+
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -36,7 +39,7 @@ pub fn main() !void {
         }, .{});
         // title
         {
-            var title: Title = .init();
+            var title: Title = .{};
             try header.append(try .init(allocator, .{}, title.element()));
         }
         // about navigation button
@@ -76,7 +79,7 @@ pub fn main() !void {
     }
     // footer
     {
-        var info_banner: InfoBanner = .init();
+        var info_banner: InfoBanner = .{};
         const footer: App.Container = try .init(allocator, .{
             .size = .{
                 .dim = .{ .y = 1 },
@@ -98,6 +101,8 @@ pub fn main() !void {
         switch (event) {
             .key => |key| {
                 if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit();
+                // test if the event handling is working correctly
+                if (key.eql(.{ .cp = zterm.input.Space })) app.postEvent(.{ .blog = allocator.dupe(u8, "./doc/test.md") catch unreachable });
             },
             .err => |err| log.err("Received {s} with message: {s}", .{ @errorName(err.err), err.msg }),
             else => {},
@@ -134,10 +139,7 @@ const zlog = @import("zlog");
 const zterm = @import("zterm");
 const App = zterm.App(
     Model,
-    union(enum) {
-        about,
-        blog,
-    },
+    Model.Pages,
 );
 
 const contents = @import("content.zig");