No body span in the JSON model, so a callable's body block cannot be sliced in either projection #203

Is your feature request related to a problem? Please describe.

codeanalyzer-java is adding a body span to its graph in codellm-devkit/codeanalyzer-java#258 (for its issue #256), under a body_ property prefix:

body_start_line, body_end_line, body_start_column, body_end_column, body_start_byte, body_end_byte

with the intent recorded in the diff as: "The body block's own offsets, under a body_ prefix. span covers the whole declaration", filled from c.getBodySpan().

This analyzer has no body span in its JSON model at all, so there is nothing to project. TSCallable (src/schema/schema.ts:296, :321) carries:

• span: TSSpan — the whole declaration, signature and decorators included
• body: Record<string, TSBodyNode> — a map of body nodes, not an extent

So "give me this function's body text without its signature" is answerable on a java graph and not on this one, and unlike the other gaps in the parity sweep this one cannot be fixed in the projection — the fact does not exist upstream to project.

Filing this separately because it is a different kind of change from its neighbours: #201 and #202 move facts that analysis.json already carries onto the graph, whereas this one adds a fact to the canonical model first.

Describe the solution you'd like

• decide the open question above, and record the answer either way
• if a field is warranted: TSCallable carries a body span in analysis.json, level-free, alongside span
• the projection carries it under java's body_ prefix — adopt those six spellings, do not coin new ones
• byte offsets are UTF-8, the Neo4j projection writes :TSCallable.code one line short of the callable's span #179 meaning, Buffer-sliced
• the checked-in graph schema snapshot is regenerated

Describe alternatives you've considered

Is a stored body span needed, or is it derivable? At L3 a callable's body{} carries @entry and @exit nodes, which may already bound the body block, in which case a consumer can compute the extent and a new field is redundant. At L1 there are only call nodes, so nothing bounds it there — which would make the field the only level-free answer. Settle this first: if L1 consumers need the body extent, the field earns its place; if only L3 consumers do, this may close as derivable.

Additional context

Scope boundary

The JSON model and, following it, the Neo4j projection. Filed out of the sweep that produced #201 and #202; it is not a prerequisite for either, and neither is a prerequisite for it.

Caveats

• The body_ names are codeanalyzer-java's. #258 coins them; a term coined twice is permanently wrong under the cross-language parity clause. That PR is unmerged at time of filing, so the spellings are proposed rather than shipped — same sequencing hazard as Neo4j projection drops module source and span byte offsets, so no span narrower than a callable resolves to text #201, and the same answer: wait, then adopt verbatim.
• Abstract, ambient and overload-only callables have no body, so the field must be genuinely absent for them rather than a zero-width span at the declaration start — otherwise a consumer cannot tell "no body" from "empty body".
• Arrow-function and expression bodies have no block. const f = () => x has a body expression, not a body block; whether its span covers x or is absent needs deciding, and java's Java-shaped answer will not settle it. This is one place this analyzer has to think for itself rather than adopt.
• schema_version does not move (Scope every destructive Neo4j statement on the can:// id prefix; retire _module .github#50), so the addition is presence-detectable only.

Definition of done

• For a fixture callable with a block body, Buffer.from(source).subarray(body_start_byte, body_end_byte) is exactly the body block including its braces, and the declaration span slice strictly contains it.
• For an abstract method, an ambient declaration and an overload signature, the field is absent rather than zero-width, asserted per node.
• For an arrow function with an expression body, whatever was decided above is asserted, not left to chance.
• At least one fixture callable follows a non-ASCII character in its file, so a char-offset regression fails the slice check.
• Emitted schema matches the checked-in snapshot; bun test and bun run typecheck green.