fix(sdk): preserve partial assistant message on chat stream failure #8750

Job	Run time
Detect changes	7s
code-quality / code-quality	2m 34s
runops-guard / runops-guard	2m 15s
internal / 🧪 Unit Tests: Internal	7m 23s
e2e-webapp / 🧪 E2E Tests: Webapp	3m 41s
sdk-compat / Deno Runtime	2m 38s
packages / 🧪 Unit Tests: Packages (2, 3)	3m 17s
sdk-compat / Cloudflare Workers	2m 25s
sdk-compat / Node.js 26.4 (warp-ubuntu-latest-x64-4x)	2m 16s
sdk-compat / Node.js 24.18 (warp-ubuntu-latest-x64-4x)	2m 44s
webapp / 🧪 Unit Tests: Webapp (3, 12)	7m 23s
webapp / 🧪 Unit Tests: Webapp (1, 12)	7m 16s
sdk-compat / Node.js 20.20 (warp-ubuntu-latest-x64-4x)	2m 4s
sdk-compat / Bun Runtime	2m 32s
webapp / 🧪 Unit Tests: Webapp (6, 12)	7m 7s
webapp / 🧪 Unit Tests: Webapp (7, 12)	7m 10s
sdk-compat / Node.js 22.23 (warp-ubuntu-latest-x64-4x)	1m 36s
webapp / 🧪 Unit Tests: Webapp (9, 12)	7m 15s
webapp / 🧪 Unit Tests: Webapp (4, 12)	7m 16s
packages / 🧪 Unit Tests: Packages (1, 3)	3m 37s
webapp / 🧪 Unit Tests: Webapp (2, 12)	7m 20s
webapp / 🧪 Unit Tests: Webapp (11, 12)	7m 15s
typecheck / typecheck	3m 19s
webapp / 🧪 Unit Tests: Webapp (12, 12)	7m 14s
packages / 🧪 Unit Tests: Packages (3, 3)	4m 37s
webapp / 🧪 Unit Tests: Webapp (8, 12)	7m 5s
webapp / 🧪 Unit Tests: Webapp (5, 12)	7m 16s
webapp / 🧪 Unit Tests: Webapp (10, 12)	7m 23s
e2e	0s
packages / 📊 Merge Reports	16s
webapp / 📊 Merge Reports	23s
All PR Checks	5s
	2h 14m 49s

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