feat(core/core-xml): migrate to #platform/* imports

[deyaaeldeen]

Migrate @azure/core-xml to #platform/* conditional imports.

Changes

• #platform/xml — routes XML parsing/serialization to the correct implementation per platform:
  • Node (xml.ts): uses fast-xml-parser (pure JS, no DOM dependency)
  • Browser (xml-browser.mts): uses native DOM APIs (DOMParser, XMLSerializer)
  • React Native (xml.ts): same as Node — RN has no DOM, so it uses fast-xml-parser
• Per-platform tsconfigs under config/
• Updated warp.config.yml to use per-package tsconfigs instead of root-level ones
• Added vitest.react-native.config.ts and test:react-native script
• Migrated from root-level tsconfig.*.json / tsconfig.browser.config.json to shared eng/tsconfigs/ base configs

React Native rationale

On main, the RN build accidentally fell back to xml.ts because the polyfillSuffix: "-react-native" target looked for xml-react-native.mts which did not exist. This PR makes the RN→Node mapping explicit and intentional: fast-xml-parser is pure JavaScript and works in all runtimes, while the browser implementation depends on DOM APIs (document, DOMParser, Node, XMLSerializer) that are not available in React Native.

[Copilot]

Pull request overview

This PR migrates @azure/core-xml to Warp/TypeScript’s #platform/* conditional import pattern so the package builds the correct XML implementation per target (browser DOM vs Node/React Native fast-xml-parser) and standardizes per-target TypeScript/Vitest configuration under config/ and eng/tsconfigs.

Changes:

• Switch public entrypoint to export … from "#platform/xml" and add a package.json#imports mapping for browser/react-native/default platform resolution.
• Move to per-target tsconfigs under sdk/core/core-xml/config/ and update warp.config.yml to use them.
• Add React Native Vitest config + script and align browser Vitest config to shared eng/vitestconfigs/*.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
sdk/core/core-xml/warp.config.yml	Point Warp targets at per-package tsconfigs under config/ (and drop polyfill suffix usage).
sdk/core/core-xml/vitest.react-native.config.ts	Re-export shared React Native Vitest config.
sdk/core/core-xml/vitest.browser.config.ts	Re-export shared browser Vitest config.
sdk/core/core-xml/tsconfig.json	Replace legacy references with per-target config/ references (src/test/samples/snippets).
sdk/core/core-xml/src/xml-browser.mts	Simplify parseXML implementation (async flow) and minor catch cleanup.
sdk/core/core-xml/src/index.ts	Route XML APIs through #platform/xml instead of a fixed relative import.
sdk/core/core-xml/package.json	Add imports["#platform/xml"] mapping; update scripts to use new config locations and add RN test run.
sdk/core/core-xml/eslint.config.mjs	Add local flat-config ESLint setup using config/tsconfig.lint.json.
sdk/core/core-xml/config/tsconfig.test.react-native.json	New RN test tsconfig extending shared eng/tsconfigs.
sdk/core/core-xml/config/tsconfig.test.browser.json	New browser test tsconfig extending shared eng/tsconfigs.
sdk/core/core-xml/config/tsconfig.src.react-native.json	New RN src tsconfig extending shared eng/tsconfigs.
sdk/core/core-xml/config/tsconfig.src.browser.json	New browser src tsconfig extending shared eng/tsconfigs.
sdk/core/core-xml/tsconfig.test.node.json	Removed legacy test tsconfig (replaced by config/tsconfig.test.node.json).
sdk/core/core-xml/tsconfig.test.json	Removed legacy aggregator test tsconfig (replaced by package tsconfig.json references).
sdk/core/core-xml/tsconfig.src.json	Removed legacy src tsconfig (replaced by per-target config/ tsconfigs).
sdk/core/core-xml/tsconfig.src.build.json	Removed legacy build tsconfig (replaced by per-target config/ tsconfigs).
sdk/core/core-xml/tsconfig.src.browser.json	Removed legacy browser src tsconfig (replaced by config/tsconfig.src.browser.json).
sdk/core/core-xml/tsconfig.snippets.json	Removed legacy snippets tsconfig (replaced by config/tsconfig.snippets.json).
sdk/core/core-xml/tsconfig.samples.json	Removed legacy samples tsconfig (replaced by config/tsconfig.samples.json).
sdk/core/core-xml/tsconfig.browser.config.json	Removed legacy browser test config tsconfig (replaced by config/tsconfig.test.browser.json).