fix: rebuilt stylesheet + visible explorer rows (v3.6.30)

The compiled Tailwind stylesheet (frontend/style.css) had been stale since
2026-09-22: classes introduced later were missing from it, so the Install /
Make selectable chips had no background or text colour in light mode (dark
mode only looked green because an older dark:text-emerald-400 rule matched)
and the new w-28 action column did not apply.

- Rebuilt with `npm run build` (Tailwind + appended src/contrast.css);
  verified the previously missing classes (bg-emerald-100, text-emerald-700,
  hover:bg-emerald-200, bg-red-100, bg-blue-100, w-28, ...).
- Explorer rows are visible chips now: rounded bg-gray-50 dark:bg-slate-800/60
  with a hover:bg-gray-100 highlight and the colored left accent kept (module
  rows a subtler variant), so a right-column button is unambiguously tied to
  its row; ISD/app/ELF/module rows all use the same treatment.
- AGENTS working conventions: an index.html change that introduces new
  utility classes also requires `npm run build` in frontend/.

660 frontend / 504 Python green; version 3.6.30; sw simple-v303.

pysim_simple_server/server.py

@@ -31,7 +31,7 @@ from osmocom.tlv import BER_TLV_IE
 from osmocom.utils import rpad
 
 
-VERSION = '3.6.29'
+VERSION = '3.6.30'
 
 MAX_ENVELOPE_SEGMENTS = 5  # max SMS segments for outgoing C-APDU in ENVELOPE