feat(sdk): AI SDK custom useChat transport & chat.task harness #5344

Job	Run time
typecheck / typecheck	6m 35s
e2e / 🧪 CLI v3 tests (ubuntu-latest - npm)	1m 47s
sdk-compat / Deno Runtime	2m 12s
sdk-compat / Cloudflare Workers	2m 12s
sdk-compat / Node.js 20.20 (ubuntu-latest)	2m 4s
sdk-compat / Node.js 22.12 (ubuntu-latest)	2m 1s
e2e / 🧪 CLI v3 tests (windows-latest - pnpm)	3m 53s
e2e / 🧪 CLI v3 tests (windows-latest - npm)	3m 44s
units / packages / 🧪 Unit Tests: Packages (1, 1)	8m 52s
sdk-compat / Bun Runtime	2m 6s
e2e / 🧪 CLI v3 tests (ubuntu-latest - pnpm)	2m 0s
units / internal / 🧪 Unit Tests: Internal (2, 8)	4m 21s
units / internal / 🧪 Unit Tests: Internal (4, 8)	4m 22s
units / internal / 🧪 Unit Tests: Internal (5, 8)	4m 24s
units / internal / 🧪 Unit Tests: Internal (3, 8)	4m 23s
units / internal / 🧪 Unit Tests: Internal (6, 8)	4m 23s
units / webapp / 🧪 Unit Tests: Webapp (3, 8)	3m 8s
units / webapp / 🧪 Unit Tests: Webapp (1, 8)	5m 57s
units / internal / 🧪 Unit Tests: Internal (8, 8)	2m 36s
units / internal / 🧪 Unit Tests: Internal (1, 8)	4m 4s
units / internal / 🧪 Unit Tests: Internal (7, 8)	4m 23s
units / webapp / 🧪 Unit Tests: Webapp (5, 8)	4m 26s
units / webapp / 🧪 Unit Tests: Webapp (4, 8)	5m 27s
units / webapp / 🧪 Unit Tests: Webapp (6, 8)	7m 56s
units / webapp / 🧪 Unit Tests: Webapp (8, 8)	2m 56s
units / webapp / 🧪 Unit Tests: Webapp (2, 8)	4m 20s
units / webapp / 🧪 Unit Tests: Webapp (7, 8)	5m 58s
units / internal / 📊 Merge Reports	27s
units / webapp / 📊 Merge Reports	46s
units / packages / 📊 Merge Reports	26s
	1h 52m 9s

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