feat: Expose prediction SSE streams (#3019)
* feat: expose prediction SSE streams
* docs: add streaming text example
* feat: stream predictions via accept header
* fix: bound prediction stream replay history
* fix: harden SSE prediction streaming
* fix: address SSE review feedback
* feat: make prediction streaming opt-in
* fix: match iterator CLI output in SSE opt-in test
* fix: address streaming SSE review feedback
* feat: configure streaming replay history
* fix: address streaming review regressions
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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
