docs(code-runtime-python): correct the claims the new backend invalidated

Adding a published Python backend and reordering `flush_line` left several
owning documents stating things that are no longer true.

`src/invariant.ts` justified its empty installer with "ships only the fd-3
wire-protocol codec", which the subprocess execution path contradicts. The
reason now states the actual one: every relation this backend maintains lives
in the CPython child or on the fd-3 wire, so no same-process event sequence is
observable from a listener -- the same shape the sibling worker-thread backend
uses.

The seam's `PORTABLE_RESERVED_WORDS` and `language` JSDoc, the code-runtime
README pair, and docs/subsystems/code-runtime both said only TypeScript has a
published backend. Corrected in all four, with the generated cordis catalog
regenerated for the `language` change.

The note attributed the 12x multiple to the settlement flush holding three
copies. That stopped being true when `flush_line` was reordered to drop the
pending chunks before its push: the binding worst case is the newline path's
single near-budget write. Corrected in the note (both sides) and in the test
comment that repeated it.

The note's Testing section now registers the cases this stack added, and the
Chinese side receives the O(depth) entry it never got plus the new ones -- it
had drifted from the English.

`INTERPRETER_BASELINE_BYTES` argued 64 MiB from a RESIDENT set while RLIMIT_AS
bounds address space. It now cites the bootstrap's own measurement (30.23 MiB
of mappings for `python3 -I`), making 64 MiB roughly twice the measured
baseline.

Also: a hardcoded `(:232-235)` comment reference becomes a reference by name,
a "which now walks in O(depth) too" change narrative becomes a current-state
statement, and a stray double blank line is removed.

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

@@ -66,8 +66,8 @@ export const DUNDER_MEMBER = /^__.+__$/
 /**
  * Reserved words of every portable target language (ECMAScript ∪ Python),
  * refused as {@link CodeBindingNamespace.global} / error-class names by all
- * backends. Python is a portability target here even though only the
- * TypeScript worker has a published backend. The portable-identifier contract
+ * backends, which ship for both languages: the TypeScript worker thread and
+ * the CPython subprocess. The portable-identifier contract
  * promises a namespace list valid on one backend is valid on every backend; a
  * per-language check would let `lambda` pass the TypeScript backend and fail
  * the Python one. Extending the seam with a new language means widening this
@@ -106,7 +106,7 @@ export abstract class CodeRuntime extends Service {
    * generates language-specific presentation (typed SDK stubs, usage
    * instructions) switches on it and fails loud on a language it cannot
    * present. Well-known values: `'typescript'` and `'python'`, those
-   * `dsh-tools` presents; only `'typescript'` has a published backend.
+   * `dsh-tools` presents; each has a published backend.
    */
   abstract readonly language: string