refactor: migrate the examples to fallible view and init

[meszmate]

Stacked on #132.

Item 3 from the review.

418 of the 521 catch sites in examples/ are gone. Every one of them was a rendering fallback that turned an allocation failure into output a user cannot tell apart from real content — a "?" where a number belongs, a title that silently loses its styling, a whole frame replaced by the word "Error".

-        const title = title_style.render(ctx.allocator, "Todo List") catch "Todo List";
-        const filter_text = std.fmt.allocPrint(ctx.allocator, "Filter: {s}", .{...}) catch "Filter:";
-        writer.writeAll(styled_filter) catch {};
+        const title = try title_style.render(ctx.allocator, "Todo List");
+        const filter_text = try std.fmt.allocPrint(ctx.allocator, "Filter: {s}", .{...});
+        try writer.writeAll(styled_filter);

Every view that had such a fallback now returns ![]const u8. init bodies that dropped registrations on the floor were migrated too — showcase.zig alone had 28 of these:

-        self.table.addRow(.{ "web-01", "online", "45d 3h", "0.42" }) catch {};
+        try self.table.addRow(.{ "web-01", "online", "45d 3h", "0.42" });

A row that fails to be added is a bug, not a display variation.

What was deliberately left alone

catch return .none in update, the file-open failures in file_browser, catch unreachable where a call genuinely cannot fail. Those are error handling, not fallbacks — 103 sites, and they stay.

How it was done, and how it was checked

Mechanically, then reviewed. The transform only touched catch <value> and catch {}, never catch return / catch continue / catch |err|. Verified afterwards that:

• the diff contains no removed line matching catch (return|break|continue|\|) — no control flow was rewritten
• no try landed inside a string literal or a comment (three comments that a regex pass did mangle were repaired)
• no try try, no try in a syntactically odd position
• zig build, zig build test, and zig build test -Doptimize=ReleaseSafe are all clean

42 files, 566 insertions, 566 deletions — every changed line is one of the two shapes above.