[kvlonge]

Why

A target-level time_travel_retention default was applied to every model, including views. Compilation then failed with "managed time_travel_retention is not valid for views", so a target could not set a retention default for its table-backed models without annotating every view.

Changes

• The target retention default now applies only to table-backed materializations (table, incremental, snapshot), matching how default_table_type works. Other materializations resolve it as unmanaged.
• Precedence is unchanged: the model header wins over materialization_defaults, which wins over the target.
• Retention declared explicitly on a view is still rejected.

Verification

• New CLI integration test: sqb compile with [targets.prod] time_travel_retention = "90d" passes with a view, and still fails when the view declares retention itself. The first case fails on main.
• New unit cases: an incremental model inherits the target default, and a view does not.
• Focused compile, config, retention and target tests pass (927). make check-ci passes, and the public-repository scan is clean.