fix(platform/react): a step's label shows the summary half that matches it

[amitbardos]

The AI often writes a step's summary as "present | past", for example Looking at your app | Looked at your app, and ChatStep.label in 0.3.0 shows the whole string. Seen in Tiny Sunny on the released package.

Base44's builder splits it on | and shows the half that matches the row (ExecTool.tsx, preview-tool-labels.ts in apper). The label now does the same: a step that is running or waiting shows the first half, a finished one (done, stopped, error) the last. A summary without | is unchanged.

Test: "a 'present | past' summary shows the half that matches the step, as in Base44's builder"; it fails without the fix. npm test -w @base44/platform and npm run lint pass.

Worth a patch release (0.3.1) once merged.

🤖 Generated with Claude Code

[github-actions]

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🚀 Package Preview Available! (@base44/platform)

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Install this PR's preview build with npm:

npm i @base44-preview/platform@0.3.0-pr.339.c920557

Prefer not to change any import paths? Install using npm alias so your code still imports @base44/platform:

npm i "@base44/platform@npm:@base44-preview/platform@0.3.0-pr.339.c920557"

Or add it to your package.json dependencies:

{
  "dependencies": {
    "@base44/platform": "npm:@base44-preview/platform@0.3.0-pr.339.c920557"
  }
}

• 📦 Preview Package: @base44-preview/platform@0.3.0-pr.339.c920557
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