Improve crash handling

This adds a crash handler which reports a crash (if telemetry is enabled). On a
crash, this looks for `curl` (using the PATH env), and forks the process to then
call execve. This relies on a new endpoint to be setup to accept the "report".
Also, we include very little data..I figured just knowing about crashes would
be a good place to start.

A panic handler is provided, which override's Zig default handler and hooks
into the crash handler.

An `assert` function is added and hooks into the crash handler. This is
currently only used in one place (Session.zig) to demonstrate its use. In
addition to reporting a failed assert, the assert aborts execution in
ReleaseFast (as opposed to an undefined behavior with std.debug.assert).

I want to hook this into the v8 global error handler, but only after direct_v8
is merged.

Much of this is inspired by bun's code. They have their own assert (1) and
a [more sophisticated] crashHandler (2).
:

(1) beccd01647/src/bun.zig (L2987)
(2) beccd01647/src/crash_handler.zig (L198)

build.zig

@@ -48,6 +48,7 @@ pub fn build(b: *Build) !void {
             .sanitize_c = enable_csan,
             .sanitize_thread = enable_tsan,
         });
+        mod.addImport("lightpanda", mod); // allow circular "lightpanda" import
 
         try addDependencies(b, mod, opts, prebuilt_v8_path);