ci(vue-sdk): add contract tests

[joker23]

SDK-2194

Adding fdv1 and fdv2 contract tests to vue sdk

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Note

Low Risk
Changes are limited to CI and a private contract-test package; production Vue SDK code paths are exercised for compliance, not altered for app behavior.

Overview
Adds LaunchDarkly SDK contract-test coverage for the Vue client SDK by introducing a new @launchdarkly/vue-contract-test-service workspace and wiring it into the vue GitHub Actions workflow.

The contract-test entity is a small Vite Vue app that connects to the harness adapter over WebSocket (TestHarnessWebSocket), creates clients via createClient / client.start(), and implements harness commands (evaluations, identify/track/flush, flag-change listeners) in ClientEntity, including mapping harness SDK config (endpoints, data system / connection modes, events, tags, hooks) onto client options.

CI builds the SDK and entity, starts the adapter and static app (port 5173), opens the app in headless Playwright, then runs the shared contract-tests action for FDv1 and FDv2 (version: v3), with skip lists for known gaps (streaming REPORT cases and tag-header edge cases). Root package.json registers the new workspace.

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[github-actions]

@launchdarkly/js-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 26365 bytes
Compressed size limit: 29000
Uncompressed size: 129044 bytes

[github-actions]

@launchdarkly/js-client-sdk-common size report
This is the brotli compressed size of the ESM build.
Compressed size: 38747 bytes
Compressed size limit: 39000
Uncompressed size: 212249 bytes

[github-actions]

@launchdarkly/browser size report
This is the brotli compressed size of the ESM build.
Compressed size: 179504 bytes
Compressed size limit: 200000
Uncompressed size: 831427 bytes

[github-actions]

@launchdarkly/js-client-sdk size report
This is the brotli compressed size of the ESM build.
Compressed size: 32027 bytes
Compressed size limit: 34000
Uncompressed size: 114248 bytes

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 2 additional findings.