fix(phase1): harden editor and compiler workflows

[SloppyBobbert]

Summary

• preserve draft, formula, save, and compile ownership across reloads and overlapping async operations
• separate Generate from Compile while retaining the last successful PDF and exact compile snapshot
• persist template selections, enforce staff/owner boundaries, and validate compiler requests with limits, throttling, timeouts, and generic diagnostics
• document Phase 1 evidence and the remaining infrastructure work

Verification

• frontend: 100 tests passed
• frontend: ESLint passed
• frontend: Vite production build passed
• backend: 128 tests passed with 96% coverage
• Django system check passed
• migration dry-run reported no changes
• changed Python files compiled successfully
• git diff --check passed

Deferred infrastructure

• compile throttles still require a shared cache and trusted client-IP handling for global multi-worker enforcement
• full compiler process/container, filesystem, network, CPU, memory, process-count, and output isolation remains open
• anonymous compilation should not be treated as production-safe until that infrastructure is complete

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