studio: add SafeSql foundation utilities (1/7) (#45897)

## Summary

First in a stack of seven PRs migrating the remaining `executeSql` call
sites to `SafeSqlFragment`. This PR lands pure additions — shared types
and helpers that later PRs import.

- `apps/studio/lib/postgres-types.ts` — `SafePostgresColumn` /
`SafePostgresTable` wrappers over `PGColumn` / `PGTable` that brand
`check` as `SafeSqlFragment` and add the optional `format_schema` field
- `apps/studio/lib/sql.ts` — `trimSafeSqlFragment` overload set that
preserves the brand through `.trim()`
- `apps/studio/lib/type-helpers.ts` — refine `DeepReadonly` so
primitives pass through unchanged
- `apps/studio/components/ui/SafeSqlInput.tsx` — `<Input>` wrapper that
emits `SafeSqlFragment` via `rawSql`

No consumers in this PR. The next PRs in the stack pick these up.

## Stack

This is PR 1 of 7. The full sequence:

1. **This PR** — Foundation utilities
2. `charis/safe-sql-last/2` — pg-meta columns + ColumnTypeRef cascade
3. `charis/safe-sql-last/3` — pg-meta non-column SafeSql
(functions/policies/triggers)
4. `charis/safe-sql-last/4` — Studio reports / query performance /
privileges
5. `charis/safe-sql-last/6` — Stragglers + remaining tests
6. `charis/safe-sql-last/7` — Flip `executeSql` signature from `string`
to `SafeSqlFragment`

## Test plan

- [x] `pnpm typecheck` passes for the Studio target on this branch
- [x] No runtime behavior changes — only type-level additions and a new
unused component

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

## Release Notes

* **New Features**
* Introduced SafeSqlInput component providing secure and validated SQL
query input handling with built-in constraints and error prevention.

* **Refactor**
* Enhanced internal type definitions and utilities for Postgres metadata
handling and SQL operations to improve code reliability and
maintainability.

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apps/studio/components/ui/SafeSqlInput.tsx

@@ -0,0 +1,15 @@
+import { rawSql, type SafeSqlFragment } from '@supabase/pg-meta'
+import type { ChangeEvent, ComponentProps } from 'react'
+import { Input } from 'ui-patterns/DataInputs/Input'
+
+type InputProps = ComponentProps<typeof Input>
+
+export type SafeSqlInputProps = Omit<InputProps, 'placeholder' | 'value' | 'onChange'> & {
+  placeholder?: SafeSqlFragment
+  value: SafeSqlFragment
+  onChange?: (event: ChangeEvent<HTMLInputElement>, value: SafeSqlFragment) => void
+}
+
+export const SafeSqlInput = ({ onChange, ...props }: SafeSqlInputProps) => (
+  <Input {...props} onChange={(event) => onChange?.(event, rawSql(event.target.value))} />
+)

apps/studio/lib/postgres-types.ts

@@ -0,0 +1,12 @@
+import type { PGColumn, PGTable, SafeSqlFragment } from '@supabase/pg-meta'
+
+export type SafePostgresColumn = PGColumn & {
+  check: SafeSqlFragment | null
+  // Present when sourced from pg-meta's SQL queries (e.g. `pgMeta.tables.retrieve`), absent
+  // from the legacy `/platform/pg-meta/{ref}/tables` REST endpoint.
+  format_schema?: string
+}
+
+export type SafePostgresTable = Omit<PGTable, 'columns'> & {
+  columns?: SafePostgresColumn[] | undefined
+}

apps/studio/lib/sql.ts

@@ -0,0 +1,13 @@
+import type { SafeSqlFragment } from '@supabase/pg-meta'
+
+export function trimSafeSqlFragment(fragment: SafeSqlFragment): SafeSqlFragment
+export function trimSafeSqlFragment(fragment: SafeSqlFragment | null): SafeSqlFragment | null
+export function trimSafeSqlFragment(
+  fragment: SafeSqlFragment | undefined
+): SafeSqlFragment | undefined
+export function trimSafeSqlFragment(
+  fragment: SafeSqlFragment | null | undefined
+): SafeSqlFragment | null | undefined {
+  if (fragment == null) return fragment
+  return fragment.trim() as SafeSqlFragment
+}

apps/studio/lib/type-helpers.ts

@@ -2,8 +2,12 @@ export type PlainObject<Value = unknown> = Record<string | number | symbol, Valu
 
 export type Prettify<T> = { [K in keyof T]: T[K] } & {}
 
-export type DeepReadonly<T> = T extends (infer R)[]
-  ? ReadonlyArray<DeepReadonly<R>>
-  : T extends Object
-    ? { readonly [K in keyof T]: DeepReadonly<T[K]> }
-    : T
+type Primitive = string | number | bigint | boolean | symbol | null | undefined
+
+export type DeepReadonly<T> = T extends Primitive
+  ? T
+  : T extends (infer R)[]
+    ? ReadonlyArray<DeepReadonly<R>>
+    : T extends object
+      ? { readonly [K in keyof T]: DeepReadonly<T[K]> }
+      : T