Services editor (core): cross-file service tables

Add a Services pill to the Card reader tab that shows the card's service
tables side by side:

- SERVICES_CROSS_REF: the 161-row feature cross-reference (SST/UST/EST/IST
  numbers + class) transcribed from docs/services-editor.md §A; a
  completeness test pins every non-RFU service number to exactly one row.
- Reads the four files (DF.GSM/6F38, ADF.USIM/6F38, ADF.USIM/6F56,
  ADF.ISIM/6F07) via /api/read, cached per card session; a column renders
  only for a present file (no ISIM -> no IST column).
- SST cell is on/allocated-off only (never de-allocates); UST/EST/IST are
  checkboxes; per-file Save buttons write via /api/write, preserving
  unmodelled bits and reporting each result.

Frontend 1105 + Python 1090 tests green.  (Version/sw bump deferred;
FS-check is the next step.)

docs/services-editor.md

@@ -6,6 +6,11 @@
 > `EF_IST_SERVICES`, `EF_EST_SERVICES`) cross-referenced with the filesystem
 > registry `docs/uicc/UICC_FILES.md` and the standard file tree
 > `frontend/uicc_files.json`.
+>
+> Step 4a (the cross-file Services editor: §A's cross-reference, read, render,
+> per-file save) is implemented against §A; the counts below were verified
+> against the PWA's constants by `frontend/tests/services.test.js`.  §B (the
+> filesystem check) is **not** implemented yet.
 
 **Counts:** SST **59** / UST **150** / IST **22** / EST **3** services →
 **164 feature rows** (10 SIM-only, 85 USIM-only, 5 ISIM-only, 61 shared,