docs(data-modeling): plain language, tested syntax, structured key guidance

Revision per review feedback, with every schema snippet emit-tested
against @prisma-next 0.14.0 (PostgreSQL app + MongoDB app):

- Rewrite intros in plain language: idea first, blog example second,
  terms last. Remove all em dashes. The docs-writer skill gains a
  "Teach in plain language" section codifying this for other PRs.
- Fix syntax that the published packages reject:
  @relation(from:, to:) does not exist (unsupported argument on 0.14.0
  and on main, which accepts fields/references/map/onDelete/onUpdate),
  so all examples use @relation(fields:, references:). Implicit
  many-to-many and @relation(through:) are also rejected ("use an
  explicit join model"), so the m:n section now teaches the explicit
  junction model as the working pattern and names the implicit form as
  not supported yet. Verified as PASS: composite @@id junctions,
  @@discriminator/@@base (both layouts, SQL and Mongo), Mongo type
  blocks (single + list), uuid()/autoincrement defaults.
- Fix broken rendering: bare (1:1) / (1:n) / (m:n) were parsed as
  remark directives and rendered as "(1\n)". Now backticked; verified
  intact in rendered HTML.
- Break dense guidance into scannable subsections with code blocks:
  natural vs surrogate keys (Country ISO example, User/Product with
  @unique), surrogate type choice, data type choice (zip/priceCents/
  publishedAt examples), and "Which side owns the foreign key" as an
  assertive checklist.
- MongoDB shown explicitly with tab switchers where it differs
  (primary keys), cross-links to Fundamentals for querying each shape,
  "Prompt your coding agent" sections, direct link phrasing.
- Park the DR-8679 redirect map, commented out, in next.config.mjs
  under the shared "Prisma Next URL cutover (DR-8687)" block.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: ankur-arch

.claude/skills/docs-writer/SKILL.md

@@ -118,6 +118,26 @@ Better:
 - Use exact product names: Prisma Postgres, Prisma Compute, Prisma Next. Don't shorten "Prisma Postgres" to "the database" or "Prisma Next" to "the ORM" once a page covers more than one product.
 - When you tell the reader something is automatic, show the trigger that makes it happen and how to confirm it did. "Compute injects `DATABASE_URL` automatically" needs a follow-up: "Run `prisma compute env` to confirm it's set."
 
+## Teach in plain language
+
+Open every concept with the plain-words version a newcomer can repeat, then a concrete everyday example, and only then the precise terms. Jargon may appear after the reader has the idea, never as the introduction to it.
+
+Weak (jargon-first):
+
+> Data modeling is the step where you describe the shape of your application's data: the entities it works with, the fields each entity carries, and how those entities connect. You author that description as a schema, and it compiles into a versioned contract that your code, migrations, and tooling all read from.
+
+Better (idea first, example second, terms last):
+
+> Data modeling is the process of describing the data your application needs and how that data is connected.
+>
+> For example, a blog has users, posts, and comments. A user has fields like an email and a name. These models also relate to each other: a user can write many posts, and a post can have many comments.
+>
+> In Prisma Next, you define this structure in a `contract.prisma` file. This file becomes the shared contract between your application code, database migrations, and developer tools.
+
+The same rule applies inside sections: when a paragraph packs several decisions together, split it into short subsections, one decision each, and show a code block for every option you name. Guidance that lives only in inline code (`Int @id @default(autoincrement())` mid-sentence) belongs in a fenced block with a sentence of its own.
+
+Never lean on internal vocabulary ("runtime family", "lowering", "execution stack") without a one-line plain definition at first use.
+
 ## Cut the slop
 
 Delete these on sight. They add length, not clarity.