chore(main): release 3.4.0

[tzzs]

🤖 I have created a release beep boop

3.4.0 (2026-09-20)

Features

• cli: configure custom provider headers and report usage as JSON (643411b)
• doctor: probe the upstream instead of only looking for a key (128974b)
• replace the client auto-install prompt with a plain install hint (7dde998)
• server: answer count_tokens, serve single models, and bound concurrency (45a0831)

Bug Fixes

• announce dropped tool-result images and authenticate before queueing (ec37d09)
• apply v3.4.0 code-review follow-ups (usage layering, endpoint tables, tool-result media) (e228f93)
• convert: keep tool-result images usable on Anthropic upstreams (daf933c)
• convert: keep tool-result images usable on every upstream protocol (b70e9fb)
• retry a locked state-file rename on Windows (4160069)
• streaming: read every usage token field through the provider mappers (abb17fe)

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[tzzs]

🤖 Created releases:

• v3.4.0

🌻