docs(website): fill the six Reference stubs with worked examples + output

Expand columns, relationships, indexes, constraints, inserting-and-editing-
data, and querying-and-inspecting from syntax-only stubs into full pages,
each with worked examples on the library schema and real captured app output
(structure boxes, relationship diagrams, data tables, show-lists, query
plans, cascade summaries). All output captured verbatim from the app — never
hand-drawn. Both simple- and advanced-mode forms shown where both apply;
advanced syntax verified against tests/source.

STYLE.md: record the output-block convention (plain unlabelled fence,
captured from a throwaway harness, not hand-drawn).

Verified: pnpm build clean (24 pages); no forbidden terms; internal links
and heading anchors resolve.

website/src/content/docs/reference/inserting-and-editing-data.md

@@ -1,26 +1,117 @@
 ---
 title: Inserting & editing data
-description: Add, change, and remove rows.
+description: Add, change, and remove rows — with required filters and automatic confirmation of what changed.
 sidebar:
   order: 7
 ---
 
-:::note[In progress]
-The syntax below is complete and accurate; worked examples on the library
-schema are being added.
-:::
+Once your tables exist, you fill them with rows and keep them up to date. The
+examples use the [example library](/getting-started/example-library/). After
+every write, the playground shows you the rows that changed, so you can confirm
+the effect at a glance.
+
+## Inserting rows
+
+List the columns you are providing, then the matching values:
+
+```rdbms
+insert into members (name, joined) values ('Katherine Johnson', '2024-06-01')
+```
+
+```
+  1 row(s) inserted
+┌───────────┬───────────────────┬────────────┐
+│ member_id │ name              │ joined     │
+├───────────┼───────────────────┼────────────┤
+│         3 │ Katherine Johnson │ 2024-06-01 │
+└───────────┴───────────────────┴────────────┘
+```
+
+Notice that `member_id` was filled in automatically — it is a `serial` column,
+so you leave it out of the `insert` and the database assigns the next value.
+The same applies to `shortid` columns and to any column with a
+[default](/reference/constraints/) (see [Types](/reference/types/)).
+
+## Updating rows
+
+`update` changes columns on the rows that match a filter:
+
+```rdbms
+update books set published = 1970 where book_id = 2
+```
+
+```
+  1 row(s) updated
+┌─────────┬───────────────────────────┬───────────┬───────────┬────────────────┐
+│ book_id │ title                     │ author_id │ published │ isbn           │
+├─────────┼───────────────────────────┼───────────┼───────────┼────────────────┤
+│       2 │ The Left Hand of Darkness │         1 │      1970 │ 978-0441478125 │
+└─────────┴───────────────────────────┴───────────┴───────────┴────────────────┘
+```
+
+## Deleting rows
+
+```rdbms
+delete from authors where author_id = 3
+```
+
+When the deleted row has children linked by an `on delete cascade`
+[relationship](/reference/relationships/), those children are removed too, and
+the result reports each affected relationship:
+
+```
+  1 row(s) deleted
+  related: 1 row(s) deleted in `books` for relationship `books_author` (on delete cascade)
+```
+
+## The required filter
+
+`update` and `delete` **must** have a `where` clause. This is a safety rail: it
+is far too easy to wipe or rewrite a whole table by forgetting one. When you
+really do mean every row, say so explicitly with `--all-rows`:
+
+```rdbms
+update books set published = 2000 --all-rows
+delete from loans --all-rows
+```
+
+```rdbms-syntax
+update <Table> set <col>=<value>[, ...] (where <expr> | --all-rows)
+delete from <Table> (where <expr> | --all-rows)
+```
+
+## Richer filters
+
+A `where` clause is more than simple equality. It accepts `and` / `or` /
+`not`, the comparison operators, and `like`, `is null`, `in`, and `between`:
+
+```rdbms
+delete from loans where returned_on is null and loaned_on < '2024-01-01'
+```
+
+The same expression grammar drives `show data` — see
+[Querying & inspecting](/reference/querying-and-inspecting/).
+
+## In advanced mode
+
+The simple-mode commands above already use SQL-like syntax; advanced mode is
+full SQL, including multi-row inserts and `returning`:
+
+```sql
+insert into members (name, joined) values
+  ('Katherine Johnson', '2024-06-01'),
+  ('Dorothy Vaughan', '2024-06-02')
+update books set published = 1970 where book_id = 2
+delete from authors where author_id = 3
+```
+
+## Syntax
 
 ```rdbms-syntax
 insert into <Table> [(<col>[, ...])] [values] (<value>[, ...])
-update <Table> set <col>=<value>[, ...] (where <col>=<value> | --all-rows)
-delete from <Table> (where <col>=<value> | --all-rows)
+update <Table> set <col>=<value>[, ...] (where <expr> | --all-rows)
+delete from <Table> (where <expr> | --all-rows)
 ```
 
-`update` and `delete` require a `where` clause; to act on every row you must
-opt in explicitly with `--all-rows`. Auto-generated columns (`serial`,
-`shortid`) fill themselves in, so you can leave them out of an `insert`. After
-a write, the affected rows are shown automatically.
-
-`where` accepts more than simple equality — `and` / `or` / `not`,
-comparisons, `like`, `is null`, `in`, and `between`. See
-[Querying & inspecting](/reference/querying-and-inspecting/).
+See also [Querying & inspecting](/reference/querying-and-inspecting/) and
+[Constraints](/reference/constraints/).