fix(claude): rebuild the Responses reasoning chain

A Responses caller that asked for reasoning summaries got an empty chain
of thought back: every reasoning item carried a signature and no text, so
replaying it produced a Claude thinking block with an empty thinking
field. The cause was the beta list, not the translator. Cloaked requests
always sent redact-thinking-2026-02-12, which makes Anthropic withhold
the summary text even when thinking.display is summarized.

Native Claude Code 2.1.220 treats the two as mutually exclusive: the beta
is only appended while thinking summaries are off, and the request
builder removes it again whenever a display value is attached. An
isolated 2.1.220 profile with showThinkingSummaries enabled confirms it
on the wire, still on cc_entrypoint=cli, sending display=summarized
without the beta and receiving thinking text. A direct A/B against
claude-opus-4-8 pins the effect down: with the beta the thinking text is
empty for every display value, without it and with display=summarized the
text comes back. The beta is now dropped whenever the request carries
thinking.display, which is exactly the native rule.

Two translation gaps kept the chain lossy on the way back. redacted_thinking
blocks had no Responses representation at all and vanished, even though
Anthropic requires them to be replayed verbatim; they now ride in
encrypted_content behind a marker prefix and are restored as
redacted_thinking blocks. Reasoning text was only read from summary[],
so a caller whose SDK models the text in content[] lost it; content[] is
now used as a fallback, and only as a fallback so a client that mirrors
both arrays does not replay the text twice.

An item whose encrypted_content is missing or belongs to another provider
is still dropped rather than replayed, because Anthropic rejects a
thinking block without a signature and there is nothing to synthesize.