Server: no built-in public host, no trusted proxy by default; OpenAPI server variable host (D-123)

KVITT_PUBLIC_URL is required: every command refuses to start without it (compose
always sets it). KVITT_TRUSTED_PROXY defaults to none, which the rate limiter never
resolves. contracts/openapi.yaml and the utoipa document: servers[].url
https://{host}:8443 with variable host (default kvitt.example.invalid). E-7 and E-12
examples on kvitt.example.invalid.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TQd3pEP9UeN2uifbHknQ7B

server/crates/kvitt-server/tests/common/mod.rs

@@ -22,6 +22,8 @@ use sqlx::SqliteConnection;
 use tower::ServiceExt;
 use uuid::Uuid;
 
+/// `KVITT_PUBLIC_URL` of the harness, on the reserved `.invalid` name of the examples (E-7, E-12).
+pub const PUBLIC_URL: &str = "https://kvitt.example.invalid:8443";
 pub const ADMIN_ID: &str = "0192a000-0000-7000-8000-000000000001";
 pub const MEMBER_ID: &str = "0192a000-0000-7000-8000-000000000002";
 pub const ADMIN_DEVICE_ID: &str = "0192a001-0000-7000-8000-000000000001";
@@ -151,6 +153,7 @@ impl TestApp {
         let path = dir.0.to_string_lossy().into_owned();
         let config = Config::from_lookup(|k| match k {
             "KVITT_DATA_DIR" => Some(path.clone()),
+            "KVITT_PUBLIC_URL" => Some(PUBLIC_URL.to_owned()),
             // No proxy is trusted unless a test says so.
             "KVITT_TRUSTED_PROXY" => Some("127.0.0.9".to_owned()),
             _ => None,