Launch Software Wars and simplify the learning OS

[sarthakagrawal927]

What changed

• simplifies the learning OS around Dashboard, Learn, Practice, and Wars while preserving the complete catalogue and stable detail routes
• adds one-minute Blitz and thirty-minute Tradeoff battle flows, server-owned ratings, challenges, public results, remediation, and the separate realtime Worker
• adds the additive Software Wars D1 schema and a server-only bank of 1,200 editorially audited MCQs with 4,800 option explanations and 3,600 precomputed AI answers
• adds Cloudflare RealtimeKit UI integration behind a disabled/configured provider boundary
• regenerates the JavaScript-independent public curriculum with navigation parity and includes the design/OpenSpec receipts

Review findings resolved

• challenge bearer tokens are now HMAC-derived, hashed at rest, and stable across idempotent retries
• authenticated challenge creation now reports server failure instead of silently copying a generic practice URL

Validation

• 458 Vitest tests
• TypeScript typecheck
• Biome lint
• documentation validation
• strict validation for both OpenSpec changes
• ranked Wars content gate: 1,200 active questions, 4,800 explanations, 3,600 AI answers
• 424 authoritative source URLs reachable
• additive D1 migrations applied successfully to an isolated database with a clean foreign-key check
• Wars Worker deployment dry-run
• production Vite build
• staged secret scan and pre-push hook

Deployment notes

• deploy workflow must run with apply_migrations=true
• RealtimeKit credentials and the shared realtime signing secret remain manual platform configuration
• the R2 bucket, queues, and Wars Worker are not yet provisioned in the Cloudflare account