feat: card presets move to a server-side store; the server owns the SCP80 counter (v3.8.0)

The presets lived in the browser's localStorage and the PWA wrote the SCP80
counter back after every operation, so an increment could be lost when the
response never reached the tab, when two browser contexts (or the demo origin
plus a local one) held separate copies, or when the tab was closed mid-run.
The counter is card state and the server performs every card operation, so the
store now lives next to the server:

- pysim_simple_server/presets.py: one JSON file
  (~/.pysim-simple-server/card_presets.json, --card-presets overrides; Path.home()
  resolves the same way on Windows), atomic writes (temp + fsync + os.replace),
  an RLock, stable uuid ids, the ICCID normalisation the PWA uses (digits /
  spaced / raw EF hex), a duplicate-ICCID refusal and a monotonic set_counter;
  every counter change is appended to card_presets.json.audit.jsonl.
- API: GET /api/presets (card-free), POST /api/presets and
  /api/presets/update|delete|import; the import also takes the old localStorage
  export shape - that is the migration path, there is no automatic migration.
- Operations name a preset_id and the server persists the counter they
  consumed: /api/send-ota (the plain SCP80 path reports final_cntr now too),
  the RAM install/install-app/compat steps (_ram_send_gp_apdu) and the test
  runner's SCP80 steps (_preset_counter_persist).
- PWA: the Cards tab is a thin client of the store (load on connect, CRUD via
  the API, export/import), the counter write-backs became local display syncs
  (the SCP80 form's counter input stays a deliberate human edit) and the
  SCP80/RAM bodies carry preset_id; a new pysimFetchOk() surfaces the server's
  error bodies instead of silently using them.

Policy: card keys in logs and local files are not a risk for this workbench
tool (AGENTS.md) - the store is not encrypted and no redaction is required.

Tests: tests/test_presets.py (store: ICCID forms, counter monotonicity and
wrap, atomic writes, corrupt-file recovery, import), the preset endpoints in
tests/test_fetch_routes.py (incl. the counter persistence via /api/send-ota)
and the updated PWA tests.  sw cache simple-v334.

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'simple-v333';
+const CACHE = 'simple-v334';
 const URLS = [
   'index.html',
   'help.html',