feat(ui): replace unicode icons with solid-icons

Swap emoji and unicode glyphs for Tabler components so icons inherit
currentColor and font-size and render consistently across platforms.

- add src/components/doc-icons.ts to resolve doc-entry frontmatter icon
  keys to components; frontmatter now stores semantic keys
- replace the align-*.png assets with TbOutlineAlign* icons
- render RevealManager action SVGs as components instead of injected
  innerHTML strings
- carry completion icons via an optional CompletionItem.icon field

src/components/doc-icons.ts

@@ -0,0 +1,48 @@
+/**
+ * Icon registry for built-in doc entries.
+ *
+ * Doc-entry frontmatter `icon:` values are semantic keys (e.g. `dice`), not
+ * glyphs — YAML can't reference a component. This maps each key to a Tabler
+ * icon component; unknown keys fall back to a generic file icon.
+ */
+
+import type { IconTypes } from "solid-icons";
+import {
+  TbOutlineCards,
+  TbOutlineDice5,
+  TbOutlineFile,
+  TbOutlineFileText,
+  TbOutlineGitBranch,
+  TbOutlineHash,
+  TbOutlineLink,
+  TbOutlineMapPin,
+  TbOutlinePhoto,
+  TbOutlineSparkles,
+  TbOutlineSquare,
+  TbOutlineTable,
+  TbOutlineTheater,
+  TbOutlineTypography,
+} from "solid-icons/tb";
+
+const DOC_ICONS: Record<string, IconTypes> = {
+  dice: TbOutlineDice5,
+  table: TbOutlineTable,
+  link: TbOutlineLink,
+  pins: TbOutlineMapPin,
+  font: TbOutlineTypography,
+  background: TbOutlinePhoto,
+  border: TbOutlineSquare,
+  embed: TbOutlineFileText,
+  deck: TbOutlineCards,
+  yarn: TbOutlineGitBranch,
+  gm: TbOutlineTheater,
+  player: TbOutlineDice5,
+  roll: TbOutlineDice5,
+  set: TbOutlineHash,
+  spark: TbOutlineSparkles,
+};
+
+/** Resolve a frontmatter icon key to a Tabler icon component. */
+export function docIcon(key: string): IconTypes {
+  return DOC_ICONS[key] ?? TbOutlineFile;
+}