refactor: remove Python sidecar setup from CI workflows

- Deleted the setup steps for creating a Python sidecar binary in both build.yml and package-and-publish.yml workflows.
- Removed the associated script for symlinking the system Python to the sidecar path, simplifying the CI configuration.
- Updated package installation steps to exclude Python dependencies, streamlining the build process.

scripts/setup-python-sidecar.mjs

@@ -1,54 +0,0 @@
-#!/usr/bin/env node
-/**
- * Symlink system python3 to src-tauri/runtime-skill-python-<target> for local dev.
- * Run from project root: node scripts/setup-python-sidecar.mjs
- */
-import { execSync } from 'child_process';
-import fs from 'fs';
-import path from 'path';
-import { fileURLToPath } from 'url';
-
-const __dirname = path.dirname(fileURLToPath(import.meta.url));
-const root = path.resolve(__dirname, '..');
-const binariesDir = path.join(root, 'src-tauri');
-
-function getTargetTriple() {
-  try {
-    return execSync('rustc --print host-tuple', { encoding: 'utf8' }).trim();
-  } catch {
-    const out = execSync('rustc -Vv', { encoding: 'utf8' });
-    const m = out.match(/host:\s*(.+)/);
-    if (m) return m[1].trim();
-    throw new Error('Could not get Rust target triple (rustc not found?)');
-  }
-}
-
-function getSystemPython() {
-  const isWin = process.platform === 'win32';
-  try {
-    const cmd = isWin ? 'where python' : 'which python3';
-    const out = execSync(cmd, { encoding: 'utf8' }).trim();
-    const first = out.split(/[\r\n]/)[0].trim();
-    if (first) return first;
-  } catch {}
-  throw new Error(
-    'System Python not found. Install Python 3 and ensure python3 (or python on Windows) is on PATH.'
-  );
-}
-
-const target = getTargetTriple();
-const ext = process.platform === 'win32' ? '.exe' : '';
-const sidecarName = `runtime-skill-python-${target}${ext}`;
-const sidecarPath = path.join(binariesDir, sidecarName);
-const systemPython = getSystemPython();
-
-try {
-  if (fs.existsSync(sidecarPath)) {
-    fs.unlinkSync(sidecarPath);
-  }
-  fs.symlinkSync(systemPython, sidecarPath);
-  console.log(`Linked ${sidecarName} -> ${systemPython}`);
-} catch (err) {
-  console.error(err.message);
-  process.exit(1);
-}