fix(kiloclaw): show setup errors after provision failures

[RSO]

Summary

• Adds an explicit setup-failure signal so KiloClaw onboarding renders the error step when provisioning fails before a durable instance status exists.
• Records safe provision-failure analytics for the worker platform route, including Fly operation/status labels without storing upstream HTML bodies.
• Covers personal and organization onboarding flows plus state-machine and platform route tests.

Verification

• pnpm format
• pnpm exec jest --runTestsByPath "src/app/(app)/claw/components/ClawOnboardingFlow.state.test.ts"
• pnpm exec vitest run "src/routes/platform-sanitize-error.test.ts"
• pnpm --filter web typecheck
• pnpm --filter kiloclaw typecheck
• pnpm --filter kiloclaw lint
• Pre-push hook: format check, affected typecheck, lint

Visual Changes

N/A — behavior-only change; no server/browser session started per request.

Reviewer Notes

• The client-side PostHog event intentionally records only a generic failure reason, not the raw error message.
• The worker analytics event stores sanitized error and classified label values so Fly HTML error bodies do not enter Analytics Engine.