build(docs): API data generation exceeds site job timeout

Problem

The Documentation workflow's Build site job was cancelled at its 30-minute limit while Generate API data was still building package projects. This blocks an otherwise green PR whose changes are confined to DynamoDB membership code/tests.

Evidence

• PR: #11310, head 99a39ac419ba430a128086f3b8f3b0cb653b878e
• Run: https://github.com/dotnet/orleans/actions/runs/35366768582
• Job: https://github.com/dotnet/orleans/actions/runs/35366768582/job/105671024238
• Job duration: 30m16s; conclusion cancelled.
• Generate API data was cancelled; Validate and build site never started.
• The documentation project/sample build and all .NET CI jobs passed.

Several API package builds report short MSBuild elapsed times but take much longer wall-clock intervals:

16:24:53 Building Microsoft.Orleans.Persistence.Cosmos
16:26:42 Build succeeded; Time Elapsed 00:00:01.64
16:26:42 Building Microsoft.Orleans.Reminders.AzureStorage
16:28:32 Build succeeded; Time Elapsed 00:00:01.85
16:34:02 Building Microsoft.Orleans.Transactions.AzureStorage
16:39:13 Build succeeded; Time Elapsed 00:00:01.65
16:42:50 Building Microsoft.Orleans.Dashboard
16:43:08 The operation was canceled.

Investigation

Investigate time spent outside the reported build execution (such as restore/process shutdown or runner resource contention) and whether API generation should reuse build/restore work. No underlying compiler failure is present in the captured tail.

Searched existing issues/PRs for Build site/API-generation timeouts. #11091 addresses Vitest validation/corpus timeouts in a later stage, not this API-generation stage. A targeted job retry is being attempted to distinguish transient infrastructure behavior from a repeatable problem.