fix(build): Validate platform is arm64 or x86_64

[ssiyad]

No description provided.

[greptile-apps]

Greptile Summary

Adds a runtime platform validation guard to ImageBuilder.__init__, raising ValueError for any value outside "arm64" and "x86_64", correctly ordered before self.platform is assigned.

• The allowed values match the Literal["arm64", "x86_64"] annotation already on ContextManager, keeping the two classes consistent.
• The platform parameter in __init__ is still annotated as str; narrowing it to the same Literal type would surface invalid call sites to the type checker.

Confidence Score: 5/5

The change is a small, focused guard in a constructor with correct ordering — validation before assignment — and allowed values consistent with the existing codebase.

The guard is placed correctly before self.platform is assigned, the allowed values match the Literal type already used in ContextManager, and no existing code paths are altered.

No files require special attention.

Important Files Changed

Filename	Overview
agent/builder.py	Adds a runtime guard in ImageBuilder.__init__ that raises ValueError when platform is not "arm64" or "x86_64", correctly placed before self.platform is assigned.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[ImageBuilder.__init__ called] --> B{platform in 'arm64', 'x86_64'?}
    B -- No --> C[raise ValueError]
    B -- Yes --> D[self.platform = platform]
    D --> E[ContextManager created with platform]
    E --> F[docker buildx build --platform platform]

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Prompt To Fix All With AI

Fix the following 1 code review issue. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 1
agent/builder.py:523
The `platform` parameter is typed as `str`, but the guard restricts it to the same two values already expressed as `Literal["arm64", "x86_64"]` in `ContextManager` (line 117). Using the `Literal` type here lets the type checker catch bad call sites statically instead of only at runtime.

```suggestion
        platform: Literal["arm64", "x86_64"],
```

_{Reviews (2): Last reviewed commit: "fix(build): Validate platform is arm64 o..." | Re-trigger Greptile}