v0.2.0: Fix List Jobs bug, TLS 1.3 enforcement, client_disconnect_timeout, RwLock contention

Bug fixes:
- Fix List Jobs connection reset: Add client_disconnect_timeout (5s) to prevent TLS write truncation
- Enforce TLS 1.3 only: Add with_protocol_versions(&[&TLS13]) to rustls ServerConfig
- Fix RwLock contention: Release read lock before sorting in list_jobs()
- Fix systemd service: Remove ProtectSystem=strict (blocks package management)
- Fix systemd service: Change Type=notify to Type=simple (fixes restart hangs)
- Fix systemd service: Add DEBIAN_FRONTEND=noninteractive
- Fix systemd service: Add ReadWritePaths for apt/dpkg paths

CI/CD:
- Add Ubuntu 22.04 build job to CI workflow

E2E Testing:
- Add comprehensive E2E test suite (test_e2e.py)
- Tests cover health, packages, patches, jobs, security, and reboot endpoints

Other:
- Bump version to 0.2.0
- Add lessons learned documentation

tests/e2e/certs/ca.crt

@@ -0,0 +1,12 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

tests/e2e/certs/client.crt

@@ -0,0 +1,12 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

tests/e2e/certs/client.key

@@ -0,0 +1,5 @@
+-----BEGIN PRIVATE KEY-----
+MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQg5dkQDY44tZkcnQ6M
+lGDNFyFrEvcOlnDoKfA/uTvBCtehRANCAAT8X1WUWE52l/i2I3MmlSiPgrESEJ2R
+I6CJvV2hHKirY+wJbanH39b1ebW8b+W3fuhEHPaFFcpPFEnPriA+xWvT
+-----END PRIVATE KEY-----