fix: apply saved todo config on next organize

[yujiezhang-ops]

Summary

• make saved todo extractor config usable on the next organize run without telling users to restart
• force the next todo extraction after saving config so old no-key/rules checkpoints do not skip sessions
• cover the save -> organize request path in viewer tests

Root cause

Saving the key was already persisted and read by the backend, but the frontend still told users to restart. More importantly, if a previous organize attempt ran without an LLM key, its checkpoint could make the next non-forced organize skip the same sessions. That looked like the saved key was ignored.

Verification

• npx vitest run test/viewer-session-id.test.ts
• node scripts/build-viewer-html.mjs --check
• npm run build
• diff/secret scan for API keys