Simplify action run logs viewer and add JSON download

[AaronPlave]

Summary

• Replace per-line ConsoleLog rendering in the action-run output with a new ActionRunLogs component — a tight monospace block (no chevrons, no expandable rows) so vertical text selection copies cleanly in source order, like GitHub Actions logs.
• Add a Download button in the run header that exports the full run (metadata + parameters + settings + error + results + parsed logs) as JSON via the existing downloadJSON utility.
• Move the log parser out of the Svelte file into utilities/actions.ts as parseActionLogLines with its own ParsedActionLog type, and migrate the Error block to render through ActionRunLogs too so both blocks share formatting (the red wrapper keeps the Error section visually distinct).

Test plan

• Open a run with multi-line logs (including ERROR with continuation lines). Drag-select across several rows and paste into a plain editor — output should be one line per entry with timestamps + levels, indented continuation preserved, no chevron/marker characters.
• Levels render with their colors: INFO blue, WARN yellow, ERROR red, DEBUG muted (matching ConsoleLog's palette).
• Click Download in the header → {action-name}-{runId}.json downloads. Open it: object with id, status, requestedAt, requestedBy, duration, parameters, settings, error, results, and logs: [{ timestamp, level, message, trace?, data? }, ...].
• Trigger a failing run → Error block renders inside the red wrapper using the same formatting as the Logs block.
• Trigger a successful run with results.data → Results block renders unchanged.
• Run with logs: null shows the italic "No logs" placeholder; Download button still functions.