Release v0.3.5 with loopback proxy fix

[CacinieP]

What changed

• bypass operating-system proxy discovery for loopback TeXada API bases in the Tauri desktop bridge
• retain normal proxy support for explicitly configured remote API bases
• add IPv4, IPv6, hostname, remote-base, malformed-base, and real loopback HTTP regression coverage
• bump synchronized desktop/backend/package versions to 0.3.5 and add bilingual release notes

Root cause

On proxy-enabled macOS systems, the Tauri reqwest client sent 127.0.0.1:18732 traffic through the system proxy. The FastAPI sidecar and Ollama were healthy, but the proxy returned 502 Bad Gateway, so the desktop UI showed No API.

Validation

• 299 Python tests passed; 8 optional tests skipped
• Ruff passed
• Rust cargo check passed
• 3 Rust regression tests passed, including a real loopback HTTP request with the active macOS system proxy
• npm audit: 0 vulnerabilities
• pip-audit: no known vulnerabilities
• JavaScript syntax check passed
• local macOS .app bundle built successfully