ds: simplify dynamic stream

[3AceShowHand]

What problem does this PR solve?

Issue Number: close #xxx

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[gemini-code-assist]

Summary of Changes

Hello @3AceShowHand, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refactors the dynamic stream component by removing the Area generic type parameter and standardizing the area identifier to a string. This change simplifies the dynstream API and its internal implementations across various modules, making the code cleaner and more consistent. Additionally, a minor performance optimization was applied to the ChangeFeedDisplayName struct to cache its string representation.

Highlights

• Dynamic Stream Simplification: The Area generic type parameter has been removed from the dynstream package interfaces and implementations, simplifying the API and reducing complexity.
• Area Type Standardization: The GetArea method now consistently returns a string type, and SetAreaSettings accepts a string for area identification, standardizing how areas are handled across the system.
• Performance Optimization: The ChangeFeedDisplayName struct now pre-computes and caches its string representation, improving performance for frequent string conversions by avoiding repeated concatenations.
• API Shape Validation: A new test file (api_shape_test.go) has been introduced to ensure the DynamicStream and Handler interfaces conform to the updated API shape, specifically validating the string type for area.

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[gemini-code-assist]

Code Review

This pull request simplifies the dynstream API by removing the generic Area type parameter and fixing its type to string. The changes are applied broadly across the codebase, including implementations, tests, and benchmarks. The addition of a static analysis test for the API shape is a great improvement.

My review has identified two main issues:

1. An inconsistency in how the 'area' is determined in different GetArea implementations, which could affect memory management.
2. A potential bug in the ChangeFeedDisplayName.String() method that could cause it to return an empty string when the struct is created as a literal.

I've provided detailed comments and suggestions for both issues.

[ti-chi-bot]

[FORMAT CHECKER NOTIFICATION]

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