chore(release): 1.4.2

[MartinForReal]

Rolls up everything merged since v1.4.1 (#36–#42).

Added

• [1m] context variant accepted on any model, and it now means something — context-1m-2025-08-07 is opt-in through the variant rather than derived from the catalog for every request (feat(models): accept the [1m] context variant on any model #37)
• GET /v1/models reports context_window, max_output_tokens and supports_1m_context (feat(models): accept the [1m] context variant on any model #37)
• Opt-in one-hour prompt-cache TTL via extend_cache_ttl, off by default (feat(cache): add an opt-in 1h cache_control ttl #42)

Fixed

• Streams truncated during tool-argument silence — no TCP or HTTP/2 keepalive left the socket idle long enough to be reaped (fix(stream): keep the upstream connection alive through tool-argument silence #36)
• Anthropic-surface upstream errors arrived in OpenAI's envelope, so a well-formed rejection looked malformed to the SDK (fix(anthropic): return upstream errors in the Anthropic error envelope #38)
• Gemini CLI setup wrote a configuration that could not work: doubled API version in the base URL, a model Copilot never served, and no gemini-* mappings (fix(gemini,count_tokens): make the Gemini CLI setup usable and stop stalling on rate-limited token counts #40)
• count_tokens burned up to 14s of backoff under a 429 before falling through to the local estimate it would have produced immediately (fix(gemini,count_tokens): make the Gemini CLI setup usable and stop stalling on rate-limited token counts #40)
• Generated Codex config could not start: no model_context_window, an overwritten model, and an api_key that was never passed (fix(codex): write a config the client can actually start with #41)

Changed

• Dropped the four redundant full-id [1m] alias entries from the default table (chore(config): drop the redundant [1m] alias entries from the defaults #39)

Version is a patch bump per your call, though the release does add features. cargo build --locked succeeds at 1.4.2; 155 lib + 18 bin tests pass.

Merge this and the v1.4.2 tag will trigger the release workflow.