feat(mcp): byte-exact SIE upload path + brevity and memory-first onboarding (#1954)

From the fourth E2E run: the agent correctly refused to reproduce a
104 KB SIE file token by token (silent mid-verifikat truncation) and
dead-ended to the web wizard, and its replies were walls of compliance
prose.

1. gnubok_create_sie_upload: signed same-origin upload URL (reuses the
   pending-document infra; .se/.sie/.si only, 50 MB HTTP cap).
   gnubok_sie_preflight and gnubok_import_sie accept upload_id as the
   byte-exact source, plus optional sha256 (hex of the raw bytes)
   verified on the upload_id/base64 paths so truncation is DETECTED,
   never silent. Inline content above 120k chars is refused with a
   pointer to the upload flow. Scope bookkeeping:write (same intent as
   import_sie).

2. Skill: brevity rule (max ~8 short lines per reply, one warning per
   step, no legal essays), memory-first rule (check what is already
   known before asking the opening questions), the upload-first SIE
   step, and gnubok_explain_voucher_gap after import for skipped
   voucher numbers.

3. CONNECTORS.md starter prompt rewritten memory-first so it stays
   copy-paste ready without the user's own data in it. Plugin v1.2.2.

tools/list ceiling 62K to 62.4K documented in the bench.

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

claude-plugin/.claude-plugin/plugin.json

@@ -2,7 +2,7 @@
   "name": "accounted",
   "displayName": "Accounted",
   "description": "Official Accounted plugin: Swedish double-entry bookkeeping flows for Claude. Connects your ledger over MCP and ships short workflow skills (daily bookkeeping, health check, month close, VAT, payroll, year-end) that work from the company's live data and load Swedish accounting knowledge from the product when needed. Every write is staged for your approval; nothing is booked on its own.",
-  "version": "1.2.1",
+  "version": "1.2.2",
   "author": {
     "name": "Accounted (erp-mafia)"
   },