docs: reconcile canonical memory with merged Go backend

.project-docs/00-brief/project-positioning.md

@@ -2,28 +2,36 @@
 
 ## One-line Positioning
 
-This project is {one-line project positioning}.
+智念AIGC平台 (Zhinian AIGC Platform) is a production-deployable Web workbench for AI image and video creation with organization accounts, usage tracking, and billing.
 
 ## Primary Goal
 
-The project exists to {primary project goal}.
+The project exists to give organizations an Alibaba Cloud ACK-deployable AI creation platform: prompt authoring, material upload, image generation (即梦/Jimeng 4.6 and EvoLink GPT Image 2), video generation (Seedance 2.0), task management, result download, account and role management, usage reporting, and organization billing backed by direct RDS PostgreSQL persistence.
 
 ## Target Users / Consumers
 
-- {primary user or consumer}
+- Ordinary organization members: create images and videos, manage their own account and password.
+- Organization administrators: manage members, organizations, and engine settings.
+- Super administrators: own pricing rules, wallets, ledger adjustments, and platform logs.
+- External partner systems: consume the API-key authenticated public `/api/v1` surface.
 
 ## Non-goals
 
-This project does not aim to {non-goal or boundary}.
+- This project does not aim to be a model-training, dataset, or labeling platform.
+- It is not a public social sharing site; assets stay account and organization scoped.
+- In the current version it is not a horizontally auto-scaled multi-region SaaS: one Web replica until generated assets move to shared OSS.
 
 ## Core Constraints
 
-- {core constraint}
+- Same-origin browser authentication through signed, chunked `zhinian_session` cookies with per-request account/organization/sessionVersion revalidation.
+- Production persistence fails closed: explicit RDS PostgreSQL through a server-only adapter; local JSON is development/test only.
+- Cross-instance concurrency stays in PostgreSQL: `claim_generation_jobs` for job claims and `billing_post_wallet_entry` for wallet idempotency; no process-local lock replacements.
+- Chinese-first product surfaces; production deployment targets Alibaba Cloud ACK.
 
 ## Quality Bar
 
-A good solution should {quality bar}.
+A good solution should preserve current HTTP/Cookie/authorization behavior, keep provider, billing, and storage semantics idempotent and tenant-scoped, pass the executable contract tests under `contracts/`, and remain reversible through a single-writer cutover.
 
 ## Last Reviewed
 
-{YYYY-MM-DD}
+2026-08-14