OAuth: re-key store to (server, issuer) + SEP-837/2350/2352 auth UX (#1694)

* OAuth: re-key store to (server, issuer) + SEP-837/2350/2352 auth UX (#1625)

Re-key the persisted OAuth store to (server, issuer) and add the
SEP-837/2350/2352 authorization-hardening UX. The SDK v2 auth() drives the
SEP-2352 flow off the provider's ctx.issuer; the Inspector's job is to honor it
and round-trip the issuer stamp.

SEP-2352 — issuer-bound credentials
- ServerOAuthState nests issuer-bound credentials under
  byIssuer[issuer] = { clientInformation, clientRegistrationKind, tokens }, with
  an activeIssuer pointer answering the transport's ctx-less per-request bearer
  read.
- Fix a latent bug: OAuthStorageBase re-parsed tokens/client-info through
  OAuthTokensSchema/OAuthClientInformationSchema, which strip the non-RFC
  `issuer` field and silently defeat the SDK's discardIfIssuerMismatch. The
  store re-attaches the stamp from the byIssuer key.
- BaseOAuthClientProvider threads ctx.issuer and implements
  discoveryState()/saveDiscoveryState() (activates the SDK's callback-leg
  AuthorizationServerMismatchError binding check) and invalidateCredentials().
- Lazy, migration-free upgrade: a legacy pre-1625 blob's top-level
  clientInformation/tokens are returned as an unkeyed fallback until the first
  issuer-stamped save promotes them into byIssuer.

SEP-837 — application_type
- DCR declares application_type: "native" (localhost Inspector).
- ClientSettingsForm renders RegistrationRejectedError detail and reflects DCR's
  deprecated-in-favor-of-CIMD (SEP-991) status.

SEP-2350 — step-up scope union
- Per-server onInsufficientScope (reauthorize | throw) setting wired
  ServerSettingsForm -> StoredMCPServer.oauth -> StreamableHTTPClientTransport.
- StepUpAuthModal visualizes the prior-union-challenged scope set, tagging each
  scope `new` vs `already granted`.

mcpAuth simplification
- Delete the hand-rolled authorizeWithoutRefresh (mishandled issuer stamping);
  forward forceReauthorization/skipIssuerMetadataValidation to native SDK auth()
  so both the initial and step-up paths get SEP-2352 stamping.

Vocabulary + docs
- OAuthStep gains cimd_fetch / issuer_comparison / scope_step_up (recorded on a
  step-up redirect); the Network tab labels auth requests by OAuth phase.
- v2_auth_hardening.md gains an as-built status section.

Deferred to the era-aware card: the SdkError(EraNegotiationFailed) ->
UnauthorizedError unwrap and finishAuth(URLSearchParams) form (only fire under
non-legacy negotiation).

Closes #1625

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Address @claude review: issuer-stamp source gating + clear/activeIssuer + phase over-match

- SEP-2352: stamp the issuer only when the credential actually came from the
  byIssuer slot (`fromSlot`), not merely when a slot exists. A partially-populated
  slot alongside a surviving legacy field would otherwise stamp a legacy (possibly
  cross-AS) credential with the current issuer, defeating discardIfIssuerMismatch.
- Issuer-scoped clears no longer promote the cleared issuer to `activeIssuer`
  (updateIssuerSlot gains a `setActive` flag; save paths keep the promotion).
- oauthNetworkPhase matches register/token/authorize as the final path segment
  (trailing slash tolerated) so `/token/refresh` or `/api/register/foo` no longer
  over-match.
- Tests for all three.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/web/src/components/groups/ServerSettingsForm/ServerSettingsForm.test.tsx

@@ -496,6 +496,26 @@ describe("ServerSettingsForm", () => {
     });
   });
 
+  it("invokes onOAuthChange with the chosen insufficient-scope policy (SEP-2350)", async () => {
+    const user = userEvent.setup();
+    const onOAuthChange = vi.fn();
+    renderWithMantine(
+      <ServerSettingsForm
+        {...baseHandlers}
+        onOAuthChange={onOAuthChange}
+        settings={emptySettings}
+        expandedSections={["oauth"]}
+      />,
+    );
+    await user.click(
+      screen.getByRole("textbox", { name: /Insufficient-scope/i }),
+    );
+    await user.click(screen.getByText("Throw (surface the error)"));
+    expect(onOAuthChange).toHaveBeenCalledWith(
+      expect.objectContaining({ onInsufficientScope: "throw" }),
+    );
+  });
+
   it("invokes onOAuthChange when enterprise-managed is toggled", async () => {
     const user = userEvent.setup();
     const onOAuthChange = vi.fn();

clients/web/src/components/groups/ServerSettingsForm/ServerSettingsForm.tsx

@@ -6,6 +6,7 @@ import {
   Flex,
   Group,
   NumberInput,
+  Select,
   Stack,
   Text,
   TextInput,
@@ -255,6 +256,7 @@ export function ServerSettingsForm({
       clientSecret: settings.oauthClientSecret ?? "",
       scopes: settings.oauthScopes ?? "",
       enterpriseManaged: settings.enterpriseManaged ?? false,
+      onInsufficientScope: settings.oauthOnInsufficientScope,
     };
   }
 
@@ -511,6 +513,26 @@ export function ServerSettingsForm({
                   ) : null
                 }
               />
+              <Select
+                label="Insufficient-scope response"
+                description="On a 403 insufficient_scope challenge (SEP-2350): re-authorize with the accumulated scope union, or surface the error to you."
+                data={[
+                  {
+                    value: "reauthorize",
+                    label: "Re-authorize (union scopes)",
+                  },
+                  { value: "throw", label: "Throw (surface the error)" },
+                ]}
+                value={settings.oauthOnInsufficientScope ?? "reauthorize"}
+                onChange={(value) =>
+                  onOAuthChange({
+                    ...currentOAuth(),
+                    onInsufficientScope:
+                      value === "throw" ? "throw" : "reauthorize",
+                  })
+                }
+                allowDeselect={false}
+              />
               {onClearStoredOAuth ? (
                 <Flex align="flex-start" gap="sm" wrap="wrap">
                   <ClearStoredOAuthButton onClick={onClearStoredOAuth}>