visualize DB sync stages sequentially with % completion

[thedavidmeister]

Problem

The Database Sync Status modal shows one stage label per chain (e.g. "Decoding raindex logs", "Running bootstrap", "Fetching raindex logs"). Each chain advances through a fixed pipeline of stages, but the UI surfaces only the current label without the surrounding sequence — so the user can't tell:

• which stages have completed
• which stages remain
• roughly how far through the sync each chain is

When chains spend minutes in a particular stage, the modal looks identical to a hung sync.

Proposal

Render each chain's row as a stepper / progress bar through the canonical pipeline. Concretely:

• Show all stages of the runner pipeline in order with the current one highlighted, prior ones marked complete, future ones dimmed.
• Pipeline stages from `crates/common/src/local_db/pipeline/runner/mod.rs` `TargetStage`:
  1. `ManifestFetch`
  2. `DumpDownload` (incl. bootstrap)
  3. `EngineBuild`
  4. `EngineRun` (where current sub-stages like "Fetching raindex logs" / "Decoding raindex logs" live)
  5. `Export`
• Optionally percentage = (completed-stage count + fraction-of-current-stage) / total.

The current sub-stage labels ("Fetching", "Decoding", "Running bootstrap") should appear under the active step rather than as the only thing shown.

Acceptance

• For an in-progress sync, the modal shows the full pipeline ordering for each chain with the current stage visually distinct.
• A user glancing at the modal can answer "which stages remain?" and "is this stuck or progressing?" without reading source.
• Failed syncs continue to display the underlying error text in addition to the stage indicator.