feat(sdk): AI SDK custom useChat transport & chat.task harness #5233

Job	Run time
e2e / 🧪 CLI v3 tests (windows-latest - npm)	3m 26s
typecheck / typecheck	7m 5s
e2e / 🧪 CLI v3 tests (ubuntu-latest - npm)	1m 56s
e2e / 🧪 CLI v3 tests (ubuntu-latest - pnpm)	1m 54s
e2e / 🧪 CLI v3 tests (windows-latest - pnpm)	3m 33s
sdk-compat / Cloudflare Workers	2m 33s
sdk-compat / Node.js 22.12 (ubuntu-latest)	2m 40s
sdk-compat / Bun Runtime	2m 32s
sdk-compat / Deno Runtime	2m 33s
sdk-compat / Node.js 20.20 (ubuntu-latest)	2m 37s
units / packages / 🧪 Unit Tests: Packages (1, 1)	9m 3s
units / internal / 🧪 Unit Tests: Internal (3, 8)	9m 2s
units / webapp / 🧪 Unit Tests: Webapp (1, 8)	6m 30s
units / internal / 🧪 Unit Tests: Internal (5, 8)	6m 49s
units / internal / 🧪 Unit Tests: Internal (7, 8)	5m 42s
units / webapp / 🧪 Unit Tests: Webapp (3, 8)	6m 39s
units / webapp / 🧪 Unit Tests: Webapp (4, 8)	4m 6s
units / internal / 🧪 Unit Tests: Internal (2, 8)	11m 56s
units / internal / 🧪 Unit Tests: Internal (8, 8)	2m 56s
units / internal / 🧪 Unit Tests: Internal (6, 8)	6m 15s
units / internal / 🧪 Unit Tests: Internal (1, 8)	6m 21s
units / webapp / 🧪 Unit Tests: Webapp (8, 8)	3m 0s
units / webapp / 🧪 Unit Tests: Webapp (2, 8)	4m 29s
units / webapp / 🧪 Unit Tests: Webapp (7, 8)	6m 4s
units / webapp / 🧪 Unit Tests: Webapp (6, 8)	2m 57s
units / webapp / 🧪 Unit Tests: Webapp (5, 8)	8m 19s
units / internal / 🧪 Unit Tests: Internal (4, 8)	6m 30s
units / webapp / 📊 Merge Reports	47s
units / packages / 📊 Merge Reports	21s
units / internal / 📊 Merge Reports	29s
	2h 19m 4s

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