[Skeyelab]

Closes #59.

What

A project row opens on its own when it goes 🔴, 🟡, or ⏸, and closes when it recovers. An all-green fleet sits fully collapsed, one line per project.

• Edge-triggered. Dashboard.lastStoplight records the stoplight each project was last seen at; expansion changes only when that value changes, or on a project's first sighting. Level-triggering would re-open a row on every poll and fight a user who collapsed it deliberately.
• Top-level only. d.expanded is what moves. Stage expansion (d.stagesExpanded) stays manual.
• Cursor preserved. Snapshot handling moved into applySnapshot, which resolves the cursor back to the same logical navItem after the rebuild instead of clamping the index. A stage row that disappeared falls back to its project row.
• Bookkeeping pruned. A project that leaves the config is forgotten, so it counts as a first sighting if it returns.
• ⏸ awaiting-approval rows expand alongside 🔴/🟡: they need a person, so the stage and the a / x hint should be on screen.

Nothing kicks a refresh on expand — aws-green already fetches everything each poll, and the ECS detail call keys off service health rather than expansion.

Testing

Unit tests cover: first sighting per stoplight; green→red expands; red→green collapses; a hand-collapsed row surviving repeated identical snapshots; a status change overriding a manual collapse; the cursor staying on the same row when a project above it expands; and pruning on removal. go test ./... and golangci-lint clean.

Docs: README feature bullet, and a new Auto-expansion section in CONTEXT.md.