feat(ios): view and edit JSON values on the row screen

[datlechin]

Summary

• A json or jsonb field on the row screen shows indented, with View as JSON: Text and Tree modes, Copy, and Copy Value, Copy Key and Copy Key Path on tree rows. A text column holding a JSON object or array gets the same viewer.
• Editing a JSON field opens Edit JSON: monospaced, no smart quotes, dashes or autocorrect, Format to reindent, and the line, column and reason of the first error under the text. Done and Save stay off while the JSON is invalid. The value saves as typed.
• After Save the row reads the saved columns back, so it shows what the server stored.
• Value fields in the row editor, Add Row and the filter sheet no longer turn quotes curly.
• Copy, Share and Export never write a prefix... (N KB) or [BLOB N] placeholder. The table browser loads values over 4 KB in full first. A binary value, or a cut value in query results, shows Cannot Export.
• Edit and Delete need a key that is not binary. A cut text key is read whole from its ref. A delete that leaves the row in the table shows Row Not Deleted, also under SQL Server SET NOCOUNT ON.
• Load full value on a row that is gone reports it instead of showing NULL.
• JSON export escapes control characters.
• An emptied MariaDB JSON field saves NULL, not ''.
• Number fields in Add Row get a keyboard with a minus sign.

Test plan

• Fail on main, pass here: ColumnInfoTypeFamilyTests, JSONPrettyPrinterTests, JSONOutlineTests (TableProCore), JSONValidationTests, LiteralInputTraitsTests, and the new cases in RowDetailViewModelTests, DataBrowserViewModelTests, ClipboardExporterFidelityTests.
• Changed on purpose: loadedLongTextSavesItsEdit now returns the saved text from its loader, since Save reads the value back.
• iOS 27 simulator, seeded SQLite table with a JSON column: row screen, Text and Tree, Edit JSON with a trailing comma shows Line 18, column 1: Unexpected character. with Done dimmed.

	Before	After
Row, light
Row, dark
Editing, light
Editing, dark

	Light	Dark
Text
Tree
Edit JSON

Not in this PR

• The Mac JSON editor's Save check, which accepts 01 and \q: a Mac fix of its own.
• A foreign key preview built from a binary value: Open the referenced row from a foreign key on iPhone and iPad #3636 rewrites that code.

Fixes #3637