Improve first-load latency for Skills and Channels

[hazeone]

Summary

• stop the Skills page from blocking first render on the slower clawhub list enrichment path
• cache and dedupe clawhub list results in the main process to avoid repeated cold subprocess launches
• skip the redundant config-only Channels fetch when the gateway is already running
• add focused unit coverage and an Electron E2E regression for the first-load responsiveness path

Related Issue(s)

• addresses Windows first-install slowness when opening Skills / Channels while the gateway is already up

Type of Change

• Bug fix
• New feature
• Documentation
• Refactor
• Other

Validation

• pnpm test tests/unit/skills-store-fetch-parallel.test.ts tests/unit/channels-page.test.tsx tests/unit/clawhub-service.test.ts
• node scripts/generate-ext-bridge.mjs && pnpm run build:vite
• xvfb-run -a pnpm exec playwright test tests/e2e/skills-and-channels-first-load.spec.ts
• manual walkthrough on the running app covering Channels then Skills first navigation

skills_channels_first_load_walkthrough.mp4
Channels first load
Skills first load

Checklist

• I ran relevant checks/tests locally.
• I updated docs if behavior or interfaces changed.
• I verified there are no unrelated changes in this PR.

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