Release 3.7.4: improve install flow and Forge resilience

[TypeFusion]

Summary

• rebalance the website and README install paths so VS Code Marketplace and Open VSX-compatible editors are both prominent
• streamline the floating Theme Forge panel and homepage preview/install hierarchy
• make the in-editor Theme Forge resilient on Windows with host-injected assets, staged startup, timeout handling, retry, and parallel loading
• regenerate Forge webview assets during clean CI packaging before Marketplace and Open VSX publishing
• align 3.7.4 metadata and changelog entries across extension and Obsidian surfaces

Verification

• pnpm run sync
• pnpm run verify
• pnpm run audit:generated-origin -- --staged
• clean VSIX package test with extension/media removed before packaging
• verified VSIX contains forge-ui.js, forge-worker.js, and source.json
• publish workflow YAML parsed successfully

Notes

No palette or terminal-theme payload changed in this release, so the existing Warp theme PR does not need an update. Dependency audit currently receives HTTP 410 from the retired npm audit endpoint; ignore-registry-errors prevents that registry-side outage from blocking otherwise verified CI.