GH-4507: declare a module's ancillary store once per namespace

[uniquelau]

Closes #4507

TL;DR

Adds a namespace-scoped sibling of #4477's assembly policy, for modular monoliths that keep several modules in one assembly. Additive only: no existing code changes.

opts.Policies.UseAncillaryStorageFromNamespaceContaining<OrdersModule>(typeof(IOrdersStore));

What changed

File	Change
Persistence/AncillaryStorageByNamespacePolicy.cs	New. Sibling of AncillaryStorageByAssemblyPolicy: same skip rule, same UseAncillaryStorage call, same gRPC reach. Only the match differs.
IPolicies.cs, WolverineOptions.Policies.cs	Two members next to the assembly pair, named after MessagesFromNamespace / MessagesFromNamespaceContaining<T>.
3 test files	CoreTests (routing rules), MartenTests (end to end), Grpc.Tests (reach).
4 docs pages	A short "or by namespace" addition beside each assembly section.

Behaviour

Case	Result
Handler in Orders	✅ routed
Handler in Orders.Slices (child)	✅ routed
Handler in OrdersArchive (shares a prefix)	❌ left alone (dot boundary)
Handler in Shipping (sibling)	❌ left alone
Two namespace policies in one assembly	✅ each module gets its own store
Explicit [Storage] on the handler	attribute wins, and the policy adds no frame

Matching uses the namespace of the handler / endpoint / gRPC service type, not the message.

Review guide (about 5 min)

1. AncillaryStorageByNamespacePolicy.cs: diff it mentally against the assembly policy. isInNamespace is the only new logic.
2. IPolicies.cs: the public API and XML docs.
3. ancillary_storage_by_namespace_policy.cs: the table above, as tests.

Worth a look

• IPolicies gains two members. WolverineOptions is its only implementer in the repo, and GH-4477: declare a module's ancillary store once per assembly #4477 extended it the same way.
• Version badge. The docs additions sit under the existing 6.39 badge headings. Adjust if you want a badge for the release this ships in.
• Mixed-module chains. A combined chain whose handlers span two scoped namespaces gets the first matching policy's store. That's the same rule the assembly policy already has, so nothing new is introduced.

Test runs

Suite	Result
CoreTests ~ancillary_storage	14/14 on net9.0 and net10.0 (6 existing + 8 new)
MartenTests ~ancillary_storage_by	3/3 on net10.0 (2 existing + 1 new)
Wolverine.Grpc.Tests ~ancillary_storage	5/5 on net9.0 (4 existing + 1 new)

The Marten docs snippet block is written in mdsnippets' output format (region L57–L64), so a regeneration should produce no diff.

🤖 Generated with Claude Code

[Copilot]

Copilot review overview

🟢 Approval recommended

No unresolved review issues were identified.

Review effort: Lite
Findings: None

What changed in this PR

Adds namespace-scoped ancillary storage policies for modular monoliths sharing an assembly.

Changes:

• Adds namespace-based policy APIs and implementation.
• Adds Core, Marten, and gRPC test coverage.
• Updates ancillary storage documentation.

File	Description
src/​Wolverine/​WolverineOptions.Policies.cs	Registers namespace policies.
src/​Wolverine/​Persistence/​AncillaryStorageByNamespacePolicy.cs	Implements namespace matching.
src/​Wolverine/​IPolicies.cs	Defines public policy APIs.
src/​Wolverine.Grpc.Tests/​ancillary_storage_by_namespace_reaches_grpc.cs	Tests gRPC routing.
src/​Testing/​CoreTests/​Persistence/​ancillary_storage_by_namespace_policy.cs	Tests routing behavior and boundaries.
src/​Persistence/​MartenTests/​AncillaryStores/​ancillary_storage_by_namespace.cs	Adds Marten coverage.
docs/​tutorials/​modular-monolith.md	Documents namespace-scoped usage.
docs/​guide/​durability/​polecat/​ancillary-stores.md	Documents Polecat support.
docs/​guide/​durability/​marten/​ancillary-stores.md	Documents Marten support.
docs/​guide/​durability/​fisher/​index.md	Documents Fisher support.

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