Add uv (Astral Python package manager) support

- Add uv package manager implementation following pip pattern
- Configure MITM proxy with CA bundle for PyPI packages
- Add shell integration (bash/zsh/fish/PowerShell)
- Conditional on --include-python flag
- Add 33 comprehensive E2E tests covering:
  - uv pip install/sync/compile commands
  - uv add for project dependencies
  - uv tool install for global tools
  - uv run --with for ephemeral dependencies
  - uv sync for project syncing
  - Malware blocking verification for all methods
- Update documentation and package.json
- Install uv in Docker test environment

packages/safe-chain/src/packagemanager/uv/createUvPackageManager.spec.js

@@ -0,0 +1,30 @@
+import { test } from "node:test";
+import assert from "node:assert";
+import { createUvPackageManager } from "./createUvPackageManager.js";
+
+test("createUvPackageManager", async (t) => {
+  await t.test("should create package manager with required interface", () => {
+    const pm = createUvPackageManager();
+    
+    assert.ok(pm);
+    assert.strictEqual(typeof pm.runCommand, "function");
+    assert.strictEqual(typeof pm.isSupportedCommand, "function");
+    assert.strictEqual(typeof pm.getDependencyUpdatesForCommand, "function");
+  });
+
+  await t.test("should use proxy-only approach (MITM)", () => {
+    const pm = createUvPackageManager();
+    
+    // uv uses proxy-only approach, so it doesn't scan args
+    assert.strictEqual(pm.isSupportedCommand(["pip", "install", "requests"]), false);
+    assert.strictEqual(pm.isSupportedCommand(["add", "requests"]), false);
+    assert.strictEqual(pm.isSupportedCommand([]), false);
+  });
+
+  await t.test("should return empty dependency updates", () => {
+    const pm = createUvPackageManager();
+    
+    const result = pm.getDependencyUpdatesForCommand(["pip", "install", "requests"]);
+    assert.deepStrictEqual(result, []);
+  });
+});