TSExternalSymbol has multiple versions

[georgesafta]

Describe the bug
TSExternalSymbol model out of sync

It's defined as:

class TSExternalSymbol(_Base):
 """A WALA-style phantom node: a synthetic stub for a call target OUTSIDE the project (an
 imported/required library member). An edge's ``target`` byte-matches either a real
 ``TSCallable.signature`` or a ``TSExternalSymbol.signature``, so the call graph stays
 dangling-free while still recording external (e.g. sink) calls.

 Slim: the map key in ``TSApplication.external_symbols`` IS the signature (e.g.
 ``commander.parse``), and membership already means external — so neither is repeated here."""

 name: str
 module: str

while from Neo4J it is constructed as:

def external(props: Props) -> TSExternalSymbol:
 return TSExternalSymbol(
 signature=props.get("signature", ""),
 name=props.get("name", ""),
 module=props.get("module", ""),
 kind=props.get("kind", "unknown"),
 )

A similar behavior is present in the codeanalyzer:

• https://github.com/codellm-devkit/codeanalyzer-typescript/blob/main/src/schema/schema.ts#L377C1-L380C2
• neo4j schema: https://github.com/codellm-devkit/codeanalyzer-typescript/blob/main/src/build/neo4j/schema.ts#L191

To Reproduce
Load TS model from an application with external symbols.

Expected behavior
Single model

Logs
No

Additional context
No

[rahlk]

Retired by construction 2026-07-09: under schema v2, externals re-materialize as stub nodes (documented shift 5 of the schema contract) — the dual-shape TSExternalSymbol disappears with the old model layer. Lands via #241 (epic #238).

[rahlk]

Reopening — the earlier close ('retired by construction in F3/#241') was wrong for the 1.x line: F3 is 2.x work that doesn't exist yet, and this bug is live in every 1.4.x release. Verified on main today: reconstruct.external() (reconstruct.py:175-181) passes signature and kind to TSExternalSymbol, whose extra='forbid' model declares only name+module -> ValidationError('extra_forbidden') on ANY External node, even signature=''. Sole caller is TSNeo4jBackend.get_external_symbols (neo4j_backend.py:265), so that method is broken for every app with phantom nodes (the default). Constructor audit shows no sibling reconstructors share the mismatch. 1.x fix: the reconstructor conforms to the slim model (name+module only — the map key IS the signature, per the model's own docstring). Rides 1.4.3. The 2.x/F3 supersession still stands for the model layer itself.