[kvlonge]

Why

sqb rename and sqb mv required model: and column: prefixes, so sqb rename stg_orders.amount revenue and sqb mv fact_orders models/reporting/ failed, while sqb lineage already accepted bare targets.

Changes

• sqb rename and sqb mv accept bare <model> and <model>.<column> targets; the prefixes still work.
• One target resolver shared with sqb lineage, which now also accepts the column: prefix.
• Clear errors when a target names a source, seed or function, a prefix contradicts the resource, column: has no column, or sqb mv gets a column.
• Help text, the planner rename hint, the rename and column-migration docs, README, examples README and the bundled skill show the bare form.

Verification

• Unit tests for target parsing and lineage prefix handling; an integration test for a bare column rename and a bare model mv.
• Focused refactor, lineage and planner tests, ruff, fensu check and make check-ci.