fix(sdk): preserve partial assistant message on chat stream failure #8749

Job	Run time
Detect changes	6s
code-quality / code-quality	2m 36s
e2e-webapp / 🧪 E2E Tests: Webapp	3m 11s
typecheck / typecheck	2m 35s
packages / 🧪 Unit Tests: Packages (2, 3)	3m 25s
sdk-compat / Cloudflare Workers	1m 55s
sdk-compat / Node.js 24.18 (warp-ubuntu-latest-x64-4x)	2m 12s
sdk-compat / Deno Runtime	1m 46s
packages / 🧪 Unit Tests: Packages (1, 3)	7m 5s
packages / 🧪 Unit Tests: Packages (3, 3)	5m 53s
runops-guard / runops-guard	1m 29s
sdk-compat / Node.js 26.4 (warp-ubuntu-latest-x64-4x)	2m 17s
sdk-compat / Node.js 20.20 (warp-ubuntu-latest-x64-4x)	1m 44s
sdk-compat / Bun Runtime	1m 48s
sdk-compat / Node.js 22.23 (warp-ubuntu-latest-x64-4x)	1m 23s
internal / 🧪 Unit Tests: Internal	9m 46s
e2e	0s
webapp / 🧪 Unit Tests: Webapp (7, 12)	8m 8s
webapp / 🧪 Unit Tests: Webapp (10, 12)	7m 30s
webapp / 🧪 Unit Tests: Webapp (9, 12)	7m 27s
webapp / 🧪 Unit Tests: Webapp (8, 12)	9m 57s
webapp / 🧪 Unit Tests: Webapp (4, 12)	9m 7s
webapp / 🧪 Unit Tests: Webapp (1, 12)	7m 0s
webapp / 🧪 Unit Tests: Webapp (6, 12)	6m 49s
webapp / 🧪 Unit Tests: Webapp (2, 12)	6m 58s
webapp / 🧪 Unit Tests: Webapp (12, 12)	9m 13s
webapp / 🧪 Unit Tests: Webapp (3, 12)	9m 3s
webapp / 🧪 Unit Tests: Webapp (11, 12)	7m 24s
webapp / 🧪 Unit Tests: Webapp (5, 12)	8m 38s
packages / 📊 Merge Reports	1m 54s
All PR Checks	4s
webapp / 📊 Merge Reports	1s
	2h 28m 24s

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