feat(alert): per-type colour treatment for Info/Success/Warning/Danger

[martinydeAI]

Links to issues

Fixes #196

Leantime: https://leantime.itkdev.dk/dashboard/show#/tickets/showTicket/7675

Description

Completes the colour work deferred from #93. The shared Alert
component now renders four visually distinct types instead of a
single neutral surface.

• assets/styles/app.css gains four semantic token triples under
  @theme — --color-{info,success,warning,danger}-{surface,line,ink}
  — each picked to pass WCAG AA against its own soft surface.
  Success leans emerald so it reads as a status hue and not as a
  second brand-green accent.
• templates/components/Alert.html.twig maps the type prop to
  the matching class triple; the deferred-treatment comment is
  dropped.
• The type value is renamed from error to danger (no alias),
  and the nine existing type="error" callsites are updated.
• ARIA behaviour is unchanged: warning/danger stay assertive
  (role="alert"), info/success stay polite (role="status").
• New tests/Integration/Twig/Components/AlertRenderTest.php pins
  each type's class triple + role.

Screenshot of the result

To be added — please eyeball each of the four types locally before
merging.

Checklist

• My code is covered by test cases.
• My code passes our test (all our tests).
• My code passes our static analysis suite.
• My code passes our continuous integration process.

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Details - AI specificities

Goal

Give users an at-a-glance read on message severity. Today an error
and a success notice render identically, undercutting the feedback.
#93 named the four types but shipped only the ARIA-role split,
deferring the colour treatment pending semantic tokens.

Scope

• Add four semantic token triples to the @theme block in
  assets/styles/app.css.
• Wire them through templates/components/Alert.html.twig.
• Rename the type value error → danger and migrate the nine
  existing callsites.
• New AlertRenderTest mirroring the pattern used for
  FilterPillRenderTest / FormButtonRenderTest.
• Rebuild the Tailwind bundle.

Non-goals

• No icons — the task list said "and any icon", but Alert has no
  icons today and none were introduced. Purely colour treatment.
• No new alert call-sites and no change to where alerts are
  emitted — purely the visual treatment of the existing component.
• No toast / dismissible / stacked-notification behaviour.

Decisions

• Rename error → danger without an alias. Cleaner API,
  matches the design language named in the issue, and the nine
  callsites migrate in one sweep. Trade-off: any out-of-tree
  templates referencing type="error" (none exist in this repo)
  would need to be updated.
• Success leans cool (emerald) rather than warm (green). The
  brand accent is --color-primary: #478523 (warm green-700).
  Using warm green for success would read as a second brand
  accent, which the constraint in feat(components): per-type colour treatment for Alert (Info / Success / Warning / Danger) #196 explicitly rules out.
• Token naming follows the existing surface/line/ink
  convention (--color-surface-2, --color-line, --color-ink
  already exist), giving bg-*/border-*/text-* utilities that
  read cleanly at the call site.

Verification

• task coding-standards-check → clean.
• task test → 690 tests, 2044 assertions, all green.
• Visual check pending — please load /reset-password, /login,
  /admin/settings/site, and /admin/user/list to see danger,
  success, and info surfaces in context.

Links

• Fixes feat(components): per-type colour treatment for Alert (Info / Success / Warning / Danger) #196
• Refs feat(components): shared Alert Twig component varying by type #93 (introduced the component + type prop; colour
  treatment deferred).