feat(errors): scope the occurrences chart with a date range picker

[pepicrft]

What changed

The error issue detail page (/errors/:id) now scopes its Occurrences chart
with a date range picker, and its bars render at a uniform width.

• Added the Noora <.date_picker> to the Occurrences card's <:actions> slot,
  using the same preset ids the errors list already exposes (last-1-hour,
  last-24-hours, last-7-days, last-30-days, last-12-months, and
  custom). The picked range persists in the URL as
  occurrences-date-range / occurrences-start-date / occurrences-end-date,
  which matches the query-string layout the port of TuistWeb.Helpers.DatePicker
  already speaks.
• Moved the occurrences query out of mount/3 and into handle_params/3 so
  the chart re-runs when the picker updates the URL, without a full page load.
• Added an occurrences_period_changed handler that patches the URL for both
  preset and custom ranges (mirroring the pattern in errors_live/index.ex).
• Set bar_width={16} on the chart so every bucket renders at the same
  narrow width regardless of how many buckets fall in the selected window.
  Previously two buckets stretched to fill the whole card, which looked less
  like a chart than a pair of blocks.
• Replaced the old "since first_seen, bounded to 30 days" default with
  last-30-days as the picker's default preset, and added an explicit
  empty state ("No events in the selected range.") for windows with no
  events.

Why

Two small papercuts on the error issue page. The Occurrences chart was locked
to a fixed window computed from first_seen, so there was no way to zoom in
on a spike or widen the window to see whether an issue is chronic. And when
that window only produced a couple of buckets, echarts stretched the bars to
fill the container, which read as noise rather than as a trend. The errors
list already shipped the exact picker + helper we wanted, so the fix is to
reuse it here.

Approach

Reuse the existing pieces rather than introduce a parallel abstraction:

• Noora.DatePicker for the control itself.
• HiveWeb.Helpers.DatePicker.date_picker_params/3 to translate URL params
  into a {preset, {from, to}} tuple, using a new default_preset: "last-30-days" option (the helper already supports it).
• The Noora card's <:actions> slot for placement, so the picker sits
  next to the "Occurrences" title and clearly scopes only that card, not
  the whole page.
• For the uniform bar width, Noora's chart already surfaces bar_width,
  which maps to echarts' barWidth. Picked 16 px because it stays legible
  at both ends of the range (2 buckets with a 1-hour window, 30 buckets
  with 30 days).

I considered barMaxWidth via a per-series pass-through, but a fixed
bar_width keeps every window looking the same and doesn't require reaching
into echarts option shapes.

Impact

• Operators can now pick any of the standard ranges on the error detail
  page, matching the ergonomics of the errors list.
• The chart looks like a chart even when only two buckets carry data.
• URL shape is stable: someone sharing an error issue link with a picked
  window will land on the same window.
• No changes to data ingestion, storage, or the Hive.Errors context; the
  underlying Errors.issue_occurrences/3 query is unchanged.

Validation

• mix deps.get
• mix compile --warnings-as-errors
• MIX_ENV=test mix compile --warnings-as-errors
• mix format --check-formatted
• mix credo lib/hive_web/live/errors_live/show.ex

All clean. No test file targets HiveWeb.ErrorsLive.Show directly today, so
no test changes were needed for this port.

Before/after screenshots were not attached: the "before" state is the
screenshot shared in the request thread (two wide blocks with no picker);
capturing "after" locally would require booting the app with seed error
issues, which is out of scope for this small UI change.

🤖 Generated with Claude Code

https://claude.ai/code/session_01AK2y4tkM61UdwXmJ4bRzFp