feat(electrobun): wire persistence — SQLite, 17 themes, font system

Persistence:
- bun:sqlite at ~/.config/agor/settings.db (WAL mode, 500ms busy_timeout)
- 4 tables: schema_version, settings, projects, custom_themes
- 5 RPC handlers: settings.get/set/getAll, projects get/set

Theme system (LIVE switching):
- All 17 themes ported from Tauri (4 Catppuccin + 7 Editor + 6 Deep Dark)
- applyCssVars() sets 26 --ctp-* vars on document.documentElement
- Parallel xterm ITheme mapping per theme
- theme-store.svelte.ts: Svelte 5 rune store, persists to SQLite

Font system:
- font-store.svelte.ts: UI/terminal font family + size
- Live CSS var application (--ui-font-family/size, --term-font-family/size)
- onTermFontChange() callback registry for terminal instances
- Persists all 4 font settings to SQLite

AppearanceSettings wired: 17-theme grouped dropdown, font steppers
Init on startup: restores saved theme + fonts from SQLite

ui-electrobun/src/bun/index.ts

@@ -1,6 +1,7 @@
 import path from "path";
 import { BrowserWindow, BrowserView, Updater } from "electrobun/bun";
 import { PtyClient } from "./pty-client.ts";
+import { settingsDb } from "./settings-db.ts";
 import type { PtyRPCSchema } from "../shared/pty-rpc-schema.ts";
 
 const DEV_SERVER_PORT = 9760; // Project convention: 9700+ range
@@ -96,6 +97,60 @@ const rpc = BrowserView.defineRPC<PtyRPCSchema>({
         } catch { /* ignore */ }
         return { ok: true };
       },
+
+      // ── Settings handlers ─────────────────────────────────────────────────
+
+      "settings.get": ({ key }) => {
+        try {
+          return { value: settingsDb.getSetting(key) };
+        } catch (err) {
+          console.error("[settings.get]", err);
+          return { value: null };
+        }
+      },
+
+      "settings.set": ({ key, value }) => {
+        try {
+          settingsDb.setSetting(key, value);
+          return { ok: true };
+        } catch (err) {
+          console.error("[settings.set]", err);
+          return { ok: false };
+        }
+      },
+
+      "settings.getAll": () => {
+        try {
+          return { settings: settingsDb.getAll() };
+        } catch (err) {
+          console.error("[settings.getAll]", err);
+          return { settings: {} };
+        }
+      },
+
+      "settings.getProjects": () => {
+        try {
+          const projects = settingsDb.listProjects().map((p) => ({
+            id: p.id,
+            config: JSON.stringify(p),
+          }));
+          return { projects };
+        } catch (err) {
+          console.error("[settings.getProjects]", err);
+          return { projects: [] };
+        }
+      },
+
+      "settings.setProject": ({ id, config }) => {
+        try {
+          const parsed = JSON.parse(config);
+          settingsDb.setProject(id, { id, ...parsed });
+          return { ok: true };
+        } catch (err) {
+          console.error("[settings.setProject]", err);
+          return { ok: false };
+        }
+      },
     },
 
     messages: {