Derive a Move in layer 2, with a hand-written Postgres 16 to 17 example #333

Parent

#324

What

Derive a Move in layer 2 (chapter 20, 0094):

• triggers: an engine version change in the component breaksOn names, a namespace other than the active Instance's, or an eligible node set that excludes the bound volume's node;
• the move element: source, target, method, move identity, the Stable Addresses it flips, reversible, and the bounds;
• rollback: forward-only on a Process (chapter 10), with E_MOVE_IRREVERSIBLE, E_FORWARD_ONLY_UNUSED, E_MOVE_UNSUPPORTED, E_NO_MOVE_POLICY and E_MOVE_OPEN (a second Move while one is open);
• retirement once ClusterState records the flip held past retention;
• a new worked example: platform-postgres moving from 16 to 17, with a hand-written expected/resolved.json and its refusal fixtures. This is also the second hand-written target model the Task 1 feedback asked for.

Lands in TypeScript only, after emf/ is deleted (#347), with the rendered-tree and diagnostics oracles it affects, in one pull request. The intent, effective and dependencies goldens are dropped (#346), so it adds none.

Behaviour (draft ledger row)

A change an engine's data cannot follow in place derives a Move whose source, target, method and reversibility the projection records, an irreversible one is refused unless acknowledged, an acknowledgement nothing needs is refused, and the source is retired only once its flip has held past the platform's retention.

Blocked by

#341, the map whose rewrite plan replaces the closed placement ticket #328 (see #350).