v3.20.0 (fix): the install-parameter composition - one System Specific Parameters EF

Two reported SCP80/RAM issues, both confirmed against the specs:

- docs/api.md called `stk_params` a "Hex CA TLV", but TS 102 226 8.2.1.3.2.1
  puts the CA *inside* the System Specific Parameters EF ('EF'), and the PWA
  builds `EF <len> CA <len> ...` (the SIM access domain leads the CA value as
  `01 <ad>` / `00`).  A client following the doc sent a CA at the wrong level.
- the RAM composition appended the STK part after a caller-composed
  C9+EF(quotas) prefix, producing TWO EF objects.  The card read the first
  (the quotas) and ignored the CA: the install was accepted (por_ok) but the
  toolkit parameters were never registered, so no STK menu appeared (live
  2026-10-05).  Per GPD_SPE_013 v1.1 Table 6-5 (pySim's
  gen_install_parameters) the quotas (C7/C8) and the CA share ONE EF; an
  EA-form STK part is a sibling of EF (the reference TCA loader's
  `C9 00 EF 00 EA ...`).

- server: `_compose_install_params()` (used by `_cap_install_apdu` ->
  `_cap_apdu_sequence`, hence /api/ram-install, /api/ram-install-app,
  /api/scp81/gen-install and the PWA's install script template) enforces the
  rule: a caller-composed EF plus an EF-form `stk_params`, a bare CA, a
  malformed EF and quotas next to a non-empty `install_params` are refused
  (400 / `{"ok": false}` with the fix named); with an empty `install_params`
  the quotas and an EF-form CA are composed into one EF
  (`C900 EF{C7?,C8?,CA}`), an EA part stays a sibling.
- the documented `nv_quota`/`volatile_quota` fields are now real (they were
  named in the docs but implemented nowhere): integers composing C8/C7.
- PWA: `composeRamInstallParams()` composes the same single EF itself (a
  CA-form STK field takes the quotas into its EF, the merged EF travels in
  `stk_params`), the RAM install bodies send it, the placeholder shows it
  with a note when the quotas moved into the STK EF, and a refused request
  (no steps) reports the error instead of "FAILED at step: undefined".
- docs/api.md: the corrected `stk_params` description with both accepted
  shapes, the composition rule paragraph with the refusal cases, the fixed
  example (`C90000` -> `C900`), and the /api/ram-install-app and
  /api/scp81/gen-install cross-references.
- tests: composition unit tests (merge/refusals/EA-sibling) and the
  ram-install-app 400 paths (Python); `ramQuotaTlvs`/`composeRamInstallParams`/
  `ramInstallParamsCompose` pins incl. the CA merge (Node).
  Tests: 824 frontend + 740 Python; sw cache simple-v395.

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'simple-v394';
+const CACHE = 'simple-v395';
 const URLS = [
   'index.html',
   'help.html',