fix: podtui binary crashed with 'preload not found' when launched from repo root

The embedded runtime reads the CWD bunfig.toml at startup; the repo's
top-level 'preload = ["@opentui/solid/preload"]' made the standalone die
because that module isn't bundled. Removed the ambient preload from
bunfig.toml and moved the solid transform registration to explicit
--preload flags in the start/dev scripts ([test] preload untouched).

Verified: binary boots from repo root, from a clean dir, and dev/start
still work; bun test 54 pass. No new release needed — the binaries were
never config-dependent; this was purely the repo's bunfig trap.

bunfig.toml

@@ -1,4 +1,9 @@
-preload = ["@opentui/solid/preload"]
+# NO top-level `preload` here — intentional. A compiled PodTUI binary's
+# embedded Bun runtime reads the launching process's CWD bunfig.toml, and a
+# top-level `preload` entry (e.g. "@opentui/solid/preload", which the
+# standalone cannot resolve) makes the binary die at startup with
+# "preload not found". Dev/test still get the solid transform via explicit
+# `--preload` flags in package.json and the [test] section below.
 
 [test]
 preload = "@opentui/solid/preload"