A value keeps its undeclared object as part of the predicate

[WaylandYang]

Fixes #685.

What was wrong

A fact can carry both a value and an object that the model never declared as an entity:

{"subject_ref": "k2", "predicate": "build", "object": "new energy generation", "object_ref": null,
 "value": "at least 10 GW", "quote": "SB Energy and SoftBank will build at least 10 GW of new energy generation"}

None of the literal branches in extraction.rs accepted (value, undeclared non-literal object). The fact went down the relation path, where span verification marked the object as a description. It then landed as a literal whose value was the object phrase ("new energy generation"), with an object_undeclared drop, and the number was thrown away. Written value-only, the same sentence keeps its figure. So whether "at least 10 GW", "at least $4.2 billion" and "incremental $40 million" reach the graph depended on which of two equally reasonable shapes the model chose. This explains the SB Energy exhibit losing all three in one recall round tonight (15/15 → 10/15 on that document). The shape appears in 0–1.5% of facts per round, on builds from before #637 through current dev.

What changed

A new literal branch, structure only: when a value is present and the object has no handle and isn't a name declared in the response or earlier in the document (case-insensitive), the fact is a value fact. The object phrase goes into the surface predicate (build new energy generation), so it is kept, not discarded, and the quote stays as evidence. A referenced or declared object still takes the relation path. The existing branches (value only, a quantity as object, an undeclared literal under an unknown predicate) are unchanged; they now also return the surface predicate, which is the model's predicate.

Verification

• Unit test a_phrase_beside_a_value_is_not_an_entity covers the helper: no handle and undeclared → value; handle, declared name (any case) or blank → not.
• End to end, on a real server with a scripted OpenAI-compatible endpoint returning that exact reply shape, on a copy of the bench base:

build	the build fact	drops
dev	value "new energy generation", surface build (the figure is lost)	object_undeclared
this branch	value "at least 10 GW", surface build new energy generation	none

In both builds the second fact in the reply, whose object SoftBank is declared (object_ref: e2), is an edge.

• utopia-server and utopia-extract tests: 323 passed on a migrated database. Clippy -D warnings and fmt are clean.

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