feat(entrypoints): schema, Neo4j projection and the level-free pass skeleton (unit 1)

[rahlk]

Problem

TypeScript has no entrypoint fields at all — they were de-advertised in #60 because nothing populated
them. Unit 1 of docs/design/specs/entrypoint-detection.md
(#150) lands the contract so the fields exist at every -a before any detector does: the schema,
the Neo4j projection including the report on :TSApplication, and the level-free post-pass that
stamps them.

Scope boundary

Shape only. Every callable and class is stamped entrypoints: [] / is_entrypoint: false; the report
is empty. No framework gate, no rules file, no matcher — those are units 2-5 (#72).

Goals

• TSEntrypoint and TSEntrypointReport mirror PyEntrypoint / PyEntrypointReport field for field
• entrypoints + is_entrypoint on TSCallable and TSType, stamped per-run by a pass (like
  heritage), so the cached tree stays free of them and the wire always carries them
• entrypoint_report on the application root
• Neo4j: is_entrypoint / entrypoint_frameworks on :TSClass and :TSCallable;
  entrypoint_frameworks / entrypoint_report_json on :TSApplication — python's exact projection
• Identical at every -a, asserted by a test

Caveats and known risks

• Class only, not every TSType. Python stamps PyClass; interfaces, enums, aliases and namespaces
  cannot be entrypoints. The field is declared on TSType (optional) but the pass stamps classes, and
  Neo4j declares it on :TSClass only — so a dead is_entrypoint: false never appears on an interface.
• Additive, SCHEMA_VERSION unmoved (chore(schema)!: collapse the schema version back to 2.0.0 #144). No existing field or relationship changes.
• Best-effort by contract. The pass records into report.errors rather than throwing — a failure
  here must lose flags, never the analysis.
• The report will be honest-but-empty until unit 2: frameworks_detected: [] here means "no gate
  ran", not "no frameworks". Unit 2 is what makes that distinction real.

Definition of done

• Every callable and every class in the sample-app output carries the two fields, empty
• An interface carries neither
• entrypoint_report is present and empty at the root
• The stamped fields and the report are byte-identical across -a 1..-a 4
• project() emits the four Neo4j properties and the conformance test accepts them
• bun test green, container tests run