fix(code-runtime): keep the DUNDER_MEMBER fix line-neutral in the seam

The base seam branch still carries the buggy /^__.+__$/ (rejects `____`,
which its own reserved.spec asserts must match), so this stacked branch must
keep the /^__.*__$/ correction to stay green. Reword the JSDoc to the same
line count as the base so the CodeRuntime class does not shift, leaving the
cordis services catalog anchor identical to the base and confining this
branch's footprint on the seam file to the single regex character.

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:105`](../../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`
 

packages/code-runtime/code-runtime/src/index.ts

@@ -59,9 +59,8 @@ export const RESERVED_ERROR_MEMBERS: ReadonlySet<string> = new Set([
 ])
 
 /**
- * Dunder form (`__x__`, distinct leading and trailing `__` pairs, so at least
- * four characters; the middle may be empty): object-protocol slots in Python,
- * refused as {@link RESERVED_ERROR_MEMBERS | error members} on every backend.
+ * Dunder form (`__…__`, two `__` pairs with an optionally empty middle): object-protocol
+ * slots in Python, refused as {@link RESERVED_ERROR_MEMBERS | error members} on every backend.
  */
 export const DUNDER_MEMBER = /^__.*__$/