docs(code-runtime): fix remaining dunder/backend wording and document exports in README

- index.ts: RESERVED_ERROR_MEMBERS JSDoc now says `__x__` (non-empty
  middle), matching DUNDER_MEMBER and the derivative docs; and
  PORTABLE_RESERVED_WORDS is described as covering portable *target*
  languages (Python is a later-PR backend, not yet shipped).
- types.ts + type-equiv docs: CodeBindingNamespace.global points to
  RESERVED_BINDING_GLOBALS by name with an `e.g.` sample rather than
  enumerating the set (single home), no longer implying `__debug__` is a
  seeded slot.
- Agent Note: separate `__debug__` (CPython compile-time constant) from
  the seeded bootstrap globals.
- README (en/zh): document the four exported exclusion sets and the
  portable identifier/naming contract — no cross-package link needed.
- Regenerate cordis services catalog for the shifted source line.

docs/cordis-catalog/services.md

@@ -398,7 +398,7 @@ abstract run(request: CodeRunRequest): Promise<CodeRunResult>
 
 Types: [CodeRunRequest](../core-data-structures/code-runtime.md) · [CodeRunResult](../core-data-structures/code-runtime.md)
 
-Source: [`packages/code-runtime/code-runtime/src/index.ts:102`](../../packages/code-runtime/code-runtime/src/index.ts)
+Source: [`packages/code-runtime/code-runtime/src/index.ts:104`](../../packages/code-runtime/code-runtime/src/index.ts)
 
 ## `ctx.commands` — `CommandService`