chore(wiki-v2): promote #57 platform-admin entry seam onto the durable branch - #2

…ge, DTO validation, keyset hardening

All four round-justifying (non-blocking Level-3) findings from the 7-lens review, plus overlapping Level-2
robustness folded in while in the same files:

- [Testing L3 / DevOps L3] listByPage: give it opt-in {limit,before} keyset paging (consistent with the
  members/ACL reads), and add service-attachment.pg.spec.ts — resolvePage + listByPage now execute on real
  Postgres (a raw-sql column/table typo no longer ships green), and the paging keyset walks a shared-ms tie
  with no skip / no duplicate.
- [Testing L3] Add dto-validation.spec.ts — the new class-validator DTOs (ContentSearchDto, ContentSortDto,
  ContentCursorDto, ContentListDto incl. nested sort) now run through validate(), so dropping a constraint
  (@Max/@IsUUID/@IsIn/@IsNotEmpty/@IsISO8601, …) reds a test.
- [Correctness L3] Add a real-Postgres walk for the generalized TIMESTAMP keyset (only title was walked) and
  for value='' (null-title) as a mid-walk cursor bound.
- [Security F1 / Correctness #1 / Testing P2] A malformed keyset/cursor timestamp now 400s instead of
  500-ing at the ::timestamptz cast: a shared isIsoInstant() guard (rejects Date.parse-lenient-but-PG-invalid
  values like '2026') used by parseSubCollectionQuery and the content keyset builder.
- [Correctness #2] A text sort (title/name) now REQUIRES its cursor `value` (400) instead of silently
  falling back to a timestamp `updatedAt` and paginating on the wrong boundary.
- [DevOps #3] Bump service-bridge.openapi.json version 1.1.1 → 1.2.0 (additive expansion).

Non-blocking Level ≤2 polish is deferred to a follow-up issue. Verified: nest build, 19 service-bridge suites
(179 tests), 3 real-Postgres pg specs (30 tests), eslint, import-boundary — all green.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

… content write when Redis off (docmost#344)

Two pre-existing content-write defects on the collaboration path, both found while
tracing docmost#282 and both able to lose or silently drop a page's content.

docmost#342 — a content `replace` emptied the Yjs fragment BEFORE building the new document
from the request body. If `TiptapTransformer.toYdoc` threw (a body that passed
`jsonToNode` but the Yjs transformer rejects), the connection's closing store persisted
the emptied fragment: the page was WIPED while the request also failed. Build the new
state first, then delete+apply — a conversion failure now aborts before any mutation and
the original content survives. Shared by the ordinary `updatePageContent` handler and the
docmost#282 conditional write.

docmost#344 — custom collab events route only through the RedisSync extension, so with
COLLAB_DISABLE_REDIS (single-node standalone) `handleYjsEvent('updatePageContent')`
returned undefined and `PageService.update` ignored it: a REST/`/v1` content write
returned 200 while persisting nothing. Fail that one un-routable write loudly instead.
Narrowest boundary: the supported standalone mode still boots, interactive editing (direct
Hocuspocus path) is untouched, and the docmost#282 seams keep their fail-closed `undefined`
contract.

Tests: build-before-delete leaves the fragment intact on a throwing toYdoc; the gateway
guard throws for updatePageContent with Redis off, stays quiet for best-effort events, and
routes normally with Redis on. UPSTREAM_MODIFICATIONS.md seams #2/#3 updated.

Co-Authored-By: Claude Opus 4.8 <[email protected]>