Fix .transform() failing when the table is part of a view

[viraatdas]

Fixes #586.

Table.transform() raised error in view <name>: no such table: ... when the table was referenced by a SQL view, because the transform renames the table while a view still references it.

This saves the definitions of all views (and any INSTEAD OF triggers on them), drops the views before the transform runs, then recreates them afterwards. If a view cannot be recreated because it referenced a column that the transform dropped or renamed, it raises a clear TransformError naming the view and telling the user to recreate it manually, rather than leaving the database in a broken state. It deliberately does not parse the view SQL; it relies on SQLite to report a recreate failure.

Added regression tests in tests/test_transform.py covering: a view recreated after a transform, an INSTEAD OF trigger on a view recreated, and a view referencing an unregistered custom function (which recreates fine since CREATE VIEW is lazy). The transform test file passes (62 tests).

Prepared with AI assistance.

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📚 Documentation preview 📚: https://sqlite-utils--749.org.readthedocs.build/en/749/