useGeneration (ai-react): caller-supplied `devtools` can override the framework identification

Found while reviewing the @tanstack/ai-octane port (#1000). Fixed there; ai-react has the same ordering.

Problem

packages/ai-react/src/use-generation.ts builds its devtools metadata with the hardcoded identity before the caller's spread:

devtools: {
  hookName: 'useGeneration',
  framework: 'react',
  ...opts.devtools,          // <-- caller wins
},

useGeneration is documented as public API ("You can also use it directly for custom generation types"), so callers do pass devtools. A caller supplying devtools.framework or devtools.hookName silently overrides the identity, and the devtools then misattribute the activity.

Notably ai-vue and ai-solid already spread first and are not affected — ai-react is the odd one out.

Fix

Match the sibling adapters:

 devtools: {
-  hookName: 'useGeneration',
-  framework: 'react',
-  ...opts.devtools,
+  ...opts.devtools,
+  framework: 'react',
+  hookName: 'useGeneration',
 },

Unrelated caller metadata (e.g. outputKind) still passes through; only the identity keys become non-overridable.

Test

packages/ai-octane/tests/conformance/devtools-identification.test.ts covers this by spying on the bridge factory and asserting the metadata survives a hostile devtools: { framework: 'react' }. It was verified to fail against the un-fixed ordering. The same approach ports directly to ai-react.

Affected

• @tanstack/ai-react

(ai-vue / ai-solid already correct; @tanstack/ai-octane fixed in #1000.)