6f2b322a

By: Nic Fink <n.fink@bluewin.ch>

Upgrade TOML and fix run deletion, exports, and result panels

Support TOML 1.1 multiline inline tables in runcards, replacements, and
frozen child definitions, with compatible CI validation and examples.

Run dashboard deletion in background operations with short status polls,
duplicate-request protection, and persistent errors so large histories can
be deleted without hitting the proxy timeout. Omit unset JSON metadata
fields when exporting reproducible TOML.

Display result uncertainties in parentheses notation and allow campaigns
to define targets for their combined results without passing them to
children. Include regression coverage and the run 74 PDF investigation;
the sampler adapter correction lives in its separate repository.

Validation: 324 Rust unit tests, 129 frontend tests, database integration
tests for deletion and campaign/export behavior, installation smoke test,
Clippy, frontend lint/build, and read-only export of live run 74.