[dotnet-port-api] Port A2A task-store isolation

[github-actions]

Summary

Port the upstream .NET A2A task-store isolation behavior to Go by adding a2aprovider.NewIsolationKeyScopedTaskStore and the exported IsolationKeyScopedTaskStore / TaskStoreIsolationKeyProvider API. The wrapper scopes stored task IDs and context IDs by a caller-provided isolation key, strips the scoped prefixes back off before returning tasks, adds focused A2A hosting tests, and updates the feature comparison doc. This was selected because it closes a small multi-tenant A2A hosting parity gap without pulling in the larger .NET hosting/DI surface.

Upstream reference: da056275e6cfb99f51f1bc823ce5e5c587667aae from upstream-agent-framework/main.

Ported .NET PRs

• .NET: [Experimental] Extend A2A task store with isolation key scoping agent-framework#7504 - Extend A2A task stores with isolation key scoping for multi-tenant hosts.

Breaking Changes

No. This adds an opt-in A2A hosting wrapper API; existing task-store behavior is unchanged unless hosts choose to wrap their store.

Tests and Examples

• go test ./provider/a2aprovider
• Added targeted task-store and request-handler tests for duplicate bare task IDs across tenants, scoped list/get/update behavior, strict isolation-key enforcement, and end-to-end A2A handler isolation.
• No examples were added because the change is a small hosting helper rather than a new end-user workflow.

Notes

• This ports the task-store half of the upstream isolation behavior; Go still does not mirror the broader ASP.NET hosting/DI registration surface from .NET.
• ListTasksResponse.TotalSize intentionally remains the wrapped store's total count when no context filter is supplied, matching the upstream wrapper semantics.
• Other recent upstream A2A candidates such as request-config forwarding were not included here to keep the PR narrow and avoid overlap with existing tracking work.

Generated by .NET to Go API Porting Agent · gpt54 · 285.1 AIC · ⌖ 20 AIC · ⊞ 24.2K · ◷

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Show patch preview (479 of 479 lines)

From 5fd2d35badf068ef20ef2b600039e6b228e45abe Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Thu, 6 Aug 2026 06:30:32 +0000
Subject: [PATCH] [dotnet-port-api] Port A2A task-store isolation

Add an isolation-key scoped A2A task-store wrapper so multi-tenant hosts can scope task and context identifiers without exposing prefixed IDs to callers.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 docs/dotnet-go-sdk-feature-comparison.md      |   2 +-
 .../a2aprovider/isolation_taskstore_test.go   | 217 ++++++++++++++++++
 provider/a2aprovider/taskstore.go             | 217 ++++++++++++++++++
 3 files changed, 435 insertions(+), 1 deletion(-)
 create mode 100644 provider/a2aprovider/isolation_taskstore_test.go
 create mode 100644 provider/a2aprovider/taskstore.go

diff --git a/docs/dotnet-go-sdk-feature-comparison.md b/docs/dotnet-go-sdk-feature-comparison.md
index 22f52a521..99a724f6b 100644
--- a/docs/dotnet-go-sdk-feature-comparison.md
+++ b/docs/dotnet-go-sdk-feature-comparison.md
@@ -49,7 +49,7 @@ Within overlapping features, the main misalignments are API shape and ecosystem
 | Anthropic provider | Anthropic packages and reasoning/skills/function-tool samples. | `anthropicprovider.NewAgent`, message params option. | Partial | Go has provider support, but sample coverage is smaller. |
 | Gemini/provider ecosystem | Google Gemini sample through provider adapters. | `geminiprovider.NewAgent`, generate content config option. | Aligned | .NET reaches more providers through generic `IChatClient` adapters; Go has a direct Gemini package. |
 | A2A agent client | `Microsoft.Agents.AI.A2A`, card/client extensions, task/session support. | `provider/a2aprovider`, task ID option, task ID/session helpers. | Aligned | Go exposes task IDs through options/session helpers; .NET exposes extension methods over A2A clients/cards/resolvers. |
-| A2A hosting | A2A hosting packages, ASP.NET Core hosting, sam
... (truncated)