docs(api,mcp): tool counts, changelog backfill, version-header honesty, lazy auth, endpoint map (#1929)

Brings the developer-facing API and MCP docs back in line with origin/main
(audit 2026-08-26). Docs only; no runtime behaviour changes.

- Tool counts: the server registers 153 tools; docs said 90+/100+/120.
  All now say "150+" (connect-claude, gnubok-mcp README, plugin README,
  mcp-server rules, CLAUDE.md, registry entry with refreshed updatedAt).
  Not derived from the tools array: lib/ must not import @/extensions/.
- REST changelog: backfilled the additive 2026-08 changes (#1909 report
  date ranges + PDFs, #1864 POST /companies, #1773 vat-declarations,
  #1405 PATCH settings, #1724/#1788 customer personal_number, #1809
  cash_account_id filter). API version date unchanged.
- Version headers: Gnubok-Deprecation is planned, not emitted; the
  Gnubok-Version request header is not read today (version.ts comment,
  versioning page, conventions overlay, regenerated skills/accounted-api).
- connect-claude Path A documents lazy auth (connector works before an
  account exists; sign-in on the first company-scoped call).
- MCP server README: real Anthropic SDK call sites, real resource URIs,
  pending-operations widget, public-tools/tasks/origin-guard/pii-guard.
  Rules file gains Lazy auth + feedback/tasks paragraphs.
- api-routes endpoint map regenerated from the filesystem (560 routes,
  55 families incl. v1, agent, reconciliation account-keyed, dimensions,
  peppol, rot-rut, webshop-orders, mileage, billing, skatteverket,
  receipt-hunt).
- gnubok-mcp/accounted-mcp: /settings?tab=api is the pre-redesign URL;
  now /settings/api (README + help hints, no version bump).

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

scripts/api-skill/overlays/conventions.md

@@ -66,9 +66,11 @@ imports) return `202` with an operation id; poll `GET /api/v1/operations/{id}`
 until `status` is `succeeded`/`failed`. The response shape is identical
 whether the work ran inline or queued.
 
-**Versioning.** Dated versions (current: see `meta.api_version`). Pin with the
-`Gnubok-Version` request header; responses echo it. Additive changes ship
-without a version bump; see https://app.gnubok.se/docs/api/versioning.
+**Versioning.** Dated versions (current: see `meta.api_version`). Responses
+carry the `Gnubok-Version` header; request pinning via a `Gnubok-Version`
+request header is reserved for a future breaking change and is not read
+today. Additive changes ship without a version bump; see
+https://app.gnubok.se/docs/api/versioning.
 
 **Index badges.** Every operation line below carries machine-readable
 annotations from the spec: `scope:` (required key scope), `risk:` (low/medium/