Move SealShare onto Livewire Material

Replaces maryUI and daisyUI with nonameweb/livewire-material: the Vibrant
indigo scheme, a system/light/dark theme under sealshare-theme, one top
app bar with the account menu, the upload drop zone and link-ready
moments, M3 fields, dialogs instead of wire:confirm, snackbars instead of
flashed messages, a sortable admin table, and the starter-kit cleanup.
Docker builds assets after Composer; CI drops the Flux step.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V9NnLxnPp8vaaurb3Z1MFy

docs/plans/livewire-material.md

@@ -74,8 +74,8 @@ The package's decisions are in its own plan. SealShare's:
 - **Converts after `1.0.0`, in one pass, by hand** (~150 tags; no codemod), on branch
   `material`, released as **2.0.0**.
 - **Moving SealShare to Gitea is a separate plan** — this plan works wherever it is hosted.
-- **Seed `#4f46e5` (the favicon's indigo), Tonal Spot**; Vibrant generated alongside on the
-  upload page for one visual comparison before committing.
+- **Seed `#4f46e5` (the favicon's indigo), Vibrant** — chosen after comparing it with Tonal Spot
+  on the upload page in both themes (2026-09-13): Tonal Spot read grey-lavender on this seed.
 - **Theme default `system`**, storage key `sealshare-theme`, legacy `mary-theme` adopted once.
   Appearance is a Light / Dark / System connected button group.
 - **One top app bar everywhere** — logo and site title; a theme toggle for guests, an avatar