fix: normalize PURE annotations for Vite 8 and Rolldown

[Hector Hernandez (hectorhdzg)]

Fixes invalid PURE annotation warnings emitted by Vite 8/Rolldown when consuming the SDK's dist-es5 modules.

The generated JavaScript is now parsed so that:

• PURE annotations on call and new expressions are preserved and canonicalized.
• PURE annotations on literals and other unsupported expressions are removed.
• Annotation-like text inside strings and ordinary comments remains untouched.
• Legacy PURE markers remain unchanged in TypeScript source.
• Both Rollup dist/es5 and TypeScript dist-es5 outputs use the same normalization.

Testing

Added coverage for literals, arrays, objects, functions, classes, regexes, templates, unary/binary/conditional expressions, calls, constructors, IIFEs, optional calls, multiline ESM, comments, strings, idempotency, and invalid JavaScript.

Fixes #2763
Fixes #2764

[Copilot]

🟡 Changes recommended

The new PURE normalization test file contains invalid JS/incorrect expected strings that will fail parsing/assertions, and the new acorn@^8.18.0 dependency likely requires lockfile updates for Rush/pnpm consistency.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

This PR updates the build tooling to normalize /*#__PURE__*/ / /*@__PURE__*/ annotations in generated ES5 module output so newer bundlers (Vite 8 / Rolldown) don’t emit [INVALID_ANNOTATION] warnings, while preserving valid annotations on call/new expressions.

Changes:

• Replaces regex-based PURE spacing normalization with AST-based parsing (Acorn) to canonicalize valid annotations and remove invalid ones.
• Adds a dedicated Node test (tools/pureAnnotations.test.mjs) and wires it into npm test.
• Extends size tests to detect PURE annotations applied to literals (a known invalid form for Rolldown).

File summaries

File	Description
tools/pureAnnotations.test.mjs	Adds normalization test coverage for many expression types and idempotency.
tools/pureAnnotations.mjs	Implements AST-driven PURE annotation normalization using Acorn tokens/comments.
tools/grunt-tasks/fixPureAnnotations.js	Updates the Grunt task to use the shared normalizer and handle failures.
shared/AppInsightsCore/Tests/Unit/src/ai/AppInsightsCoreSize.Tests.ts	Tightens output validation by detecting PURE-on-literal patterns.
AISKU/Tests/Unit/src/AISKUSize.Tests.ts	Same PURE validity checks for AISKU bundle outputs.
package.json	Adds test:pure-annotations and the acorn devDependency.
.github/copilot-instructions.md	Adds a repository branch naming convention guideline.

Review details

Suppressed comments (4)

tools/pureAnnotations.test.mjs:50

• These expected strings are missing the opening /* of the PURE comment; canonicalizePureAnnotations() emits /*#__PURE__*/..., so the assertions will fail.

    {
        expected: "var value = /*#__PURE__*/namespace.factory();",
        input: "var value = /* #__PURE__ */ namespace.factory();"
    },

tools/pureAnnotations.test.mjs:54

• This expected output is missing the opening /* for the PURE comment, so the assertion won't match the normalized output.

    {
        expected: "var value = /*#__PURE__*/(function () {})();",
        input: "var value = /* #__PURE__ */ (function () {})();"
    },

tools/pureAnnotations.test.mjs:58

• This expected output is missing the opening /* for the PURE comment, so the assertion won't match the normalized output.

    {
        expected: "var value = /*#__PURE__*/(0, factory)();",
        input: "var value = /* #__PURE__ */ (0, factory)();"
    },

tools/grunt-tasks/fixPureAnnotations.js:80

• The success log still says "Canonicalized" even though the task now removes invalid annotations as well; updating wording to "Normalized" would better reflect what happened.

            grunt.log.ok("Canonicalized PURE annotations: checked " + filesChecked + " file(s), updated " + filesChanged + " file(s).");

• Files reviewed: 7/7 changed files
• Comments generated: 3
• Review effort level: Lite

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