`pack_rollup_1h` rollup table is written, but not used

## Problem

`pack_rollup_1h` is written daily by [`plugins/schedule_soh_daily.py`](plugins/schedule_soh_daily.py)
but the rollup table is **never read** by anything (no UI panel, no other plugin, no example query, no test assertion) in the repo. `grep -r pack_rollup` returns only:

- the plugin that writes it
- the plugin's unit test
- schema/architecture docs that describe it
- the README row in the trigger table

## Why it's a problem

1. Doesn't show off the feature: the demo proves the schedule trigger runs (the plugin executes and writes), but
doesn't prove it's *useful*--for example, showing that the dashboard's weekly view
is fast because it reads from the rollup, not the raw table.

2. Missing motivation as a Core demo: rollup tables let you sidestep Core's limited query window. The demo writes a rollup but then never queries beyond 72 hours

## Suggestion

**Wire a UI panel to it.** Add a "30-day SoH trend" or "weekly min-voltage
per pack" chart that reads from `pack_rollup_1h`. This gives the demo a concrete reason to recommend a
rollup pattern (Enterprise) or document the 72h limitation (Core).

Start with plugins/schedule_soh_daily.py and its unit test, then review the schema/architecture docs and README trigger table to understand pack_rollup_1h. Trace the existing demo UI entry points, which are not named in the issue, and determine where a 30-day SoH or weekly voltage panel belongs. Done means a UI view reads the rollup and demonstrates its longer-window purpose, with relevant coverage or documentation updated.

Written by the indexing model from the issue text.