Move the hexos-test harness apps to v6 with their actions and widgets

[eschultz]

hexos-test, hexos-test-fail and hexos-test-inline move to the v6 install script format, and hexos-test gains the harness actions and widgets that hexos-platform's app surface E2E specs (19-app-surfaces/2 and 3) need. The v6 versions only existed on feature/app-actions-widgets (#38), which isn't ready to merge, so every catalog sync put the v5 hexos-test back on dev main.

The three files are copied unchanged from #38's branch, and nothing else from #38 comes with them. The hook scripts they call (hexos-test/hooks.ts, hexos-test-fail/hooks.ts) are already on staging and identical on both branches, so #38 will still merge cleanly on these files.

What changes:

• Lifecycle hooks move to the v6 shape (events, title, optional on the hook). Run through platform staging's runnableHooksFromScript, every lifecycle hook in all three apps matches its v5 version: same ids, events, entry points, optional flags, timeouts, retries and upgrade range, and the same install consent row.
• hexos-test adds 8 actions (succeed, fail, run once, availability and visibility conditions, an unknown condition type that must stay hidden, a file browser action, a widget button) and 2 widgets.

All three apps are custom and internal, and this PR targets staging only.

Testing:

• ✅ bun _lib/validate.ts: 52 install scripts, 0 errors
• ✅ _lib typecheck passes
• ✅ Platform staging's parser (parseAppHooksV6) reports no errors for any of the three, and the v5 and v6 runnable hooks match field by field
• ✅ The same v6 hexos-test script, set on dev main's catalog row by hand, ran the 19-app-surfaces specs on a 25.10.7 lab box on 2026-10-03