refactor(middleware): handle URI parsing safely in cookie and redirect services

[spellsaif]

Safely handle http::Uri to reqwest::Url parsing in CookieService and TowerRedirectPolicy, eliminating potential .expect() panic sites on invalid or relative URIs.

Motivation & Problem

CookieService and TowerRedirectPolicy used .expect("invalid URL") when converting req.uri() or redirect previous targets. If custom Tower stacks pass origin-form or relative URIs (e.g. /api/v1/resource), Url::parse returns Err(RelativeUrlWithoutBase), causing an unexpected library panic.

Solution

• In CookieService: Safely convert req.uri() with .ok(). If req.uri() is relative, gracefully skip cookie header insertion and cookie response extraction for that request without panicking.
• In TowerRedirectPolicy: Return Err(crate::error::builder(e)) instead of panicking on invalid URLs.

Testing

• cargo check --features cookies passes cleanly.