[Cosmos] Add account-controlled availability strategy for PPAF

[Abhijeet Mohanty (jeet1995)]

Description

Add account-level control of availability strategy when PPAF is enabled.

• Honor disableCrossRegionalHedging at bootstrap and on every account refresh, including hedging-only updates.
• Suppress default and explicit hedging only while PPAF is enabled; preserve PPCB and timeout policies.
• Expose the effective state in diagnostics without retaining the client or rebuilding PPCB configuration.
• Include unit tests and nine live E2E scenarios for reads, readAll, readMany, queries, PPCB recovery, and PPAF-off precedence.

Related implementation: Azure/azure-cosmos-dotnet-v3#5829

Validation

• RxDocumentClientImplTest: 10 tests passed in Maven unit verification.
• Account-response wrapper: 8 invocations passed in Maven unit verification.
• Clean reactor verification and git diff --check passed. Revapi emitted scanner exceptions for existing internal nested classes; API-analysis completeness is not established by build success.
• Live multi-region E2E validation passed on de0cf5b: 18 tests, 0 failures, 0 errors, 0 skips, 0 flakes (Direct TCP and Gateway). Maven reactor verify completed with BUILD SUCCESS on 2026-09-11 at 19:38:32 -04:00. The query partitionKey/feedRange helper is repaired, and gateway cancellation records are preserved for non-hedged feeds. The six-case gateway cancellation regression and affected unit-test classes also pass. PR remains a draft as requested.

Live verification: run Maven verify -Pmulti-region with -Dit.test=PerPartitionAutomaticFailoverE2ETests#testAccountControlledHedgingFromBootstrap from sdk/cosmos, selecting azure-cosmos,azure-cosmos-test,azure-cosmos-tests with -am.

All SDK Contribution checklist:

• No public API breaking changes introduced.
• CHANGELOG updated.
• Contribution guidelines read.

General Guidelines and Best Practices

• Clear, informative title and scoped commits.

Testing Guidelines

• Test coverage included.
• Live multi-region E2E validation completed successfully on the latest revision.

Change-feed diagnostics regression follow-up

• Commit c4f93d1 guards gateway cancellation diagnostics with per-subscription completion state. A downstream cancellation after a delivered 200/304 response no longer adds a synthetic timeout record; in-flight cancellations retain their diagnostics.
• Reproduced the reported expected-one/actual-two record failure with three focused query/change-feed cases before applying the fix.
• ChangeFeedTest.changeFeed_cosmosDiagnostics: 2 live cases passed (the test constructor creates an internal Gateway client; inherited report labels are misleading).
• RxGatewayStoreModelTest and RxDocumentClientImplTest: 92 unit tests passed, with no failures or skips.
• Shortened the serialized diagnostic key to isHedgingDisabledByAccount as requested.
• Live PPAF matrix passed on c4f93d1: 18 tests, 0 failures, 0 errors, 0 skips, 0 flakes across Direct TCP and Gateway. Maven test-compile plus Failsafe integration-test/verify completed with BUILD SUCCESS on 2026-09-14 at 17:15:34 -04:00. Together with the 2 passing live change-feed diagnostics cases and 92 passing related unit tests, this validates the duplicate-diagnostics repair and shortened diagnostic key. PR remains a draft as requested.

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[Abhijeet Mohanty (jeet1995)]

/azp run java - cosmos - tests

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[Abhijeet Mohanty (jeet1995)]

/azp run java - cosmos - tests

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[Abhijeet Mohanty (jeet1995)]

/azp run java - cosmos - tests

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