chore: add CI workflows, dev launcher, and linux capability schema

.github/workflows/check.yml: cargo check on Linux + Windows + macOS
  plus Svelte/Vite build on every push to main and every PR. Fast
  feedback without paying for the full release build.

.github/workflows/build.yml: cross-platform release build producing
  .AppImage/.deb (Linux), .msi/.exe (Windows), .dmg (macOS). Triggers
  on v* tag push (attaches to a draft GitHub Release) or manual
  workflow_dispatch. Signing stubs commented out pending cert decisions.

run.sh: dev launcher that starts Vite, waits for port 1420, then runs
  tauri dev with beforeDevCommand blanked to avoid a second Vite spawn.
  Restores tauri.conf.json on exit via trap.

src-tauri/gen/schemas/linux-schema.json: Tauri-generated capability
  schema for Linux; the other platform schemas (desktop, windows) were
  already committed. Adds the missing sibling.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

run.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+# Kon dev launcher. Starts Vite first, waits for it to bind port 1420,
+# then runs Tauri without triggering a second Vite instance.
+# For performance testing use: npm run tauri build
+set -euo pipefail
+cd "$(dirname "$0")"
+
+export LIBCLANG_PATH=/usr/lib64/llvm21/lib64
+
+printf 'Starting Vite dev server...\n' >&2
+npm run dev &
+VITE_PID=$!
+
+until curl -sf http://localhost:1420 > /dev/null 2>&1; do sleep 0.5; done
+printf 'Vite ready. Launching Tauri...\n' >&2
+
+# Blank beforeDevCommand so Tauri doesn't spawn a second Vite
+sed -i 's/"beforeDevCommand": "npm run dev"/"beforeDevCommand": ""/' src-tauri/tauri.conf.json
+
+cleanup() {
+    sed -i 's/"beforeDevCommand": ""/"beforeDevCommand": "npm run dev"/' src-tauri/tauri.conf.json
+    kill "$VITE_PID" 2>/dev/null || true
+}
+trap cleanup EXIT INT TERM
+
+npx tauri dev