fix(build): render Nextcloud login page via askama, not include_str!(OUT_DIR)

The SvelteKit migration gated build.rs's static-dist/OUT_DIR generation
behind OXICLOUD_RUST_ASSETS=1 (early return), but login_v2_handler.rs
still embedded the page with
`include_str!(concat!(env!("OUT_DIR"), "/nextcloud-login.html"))`. With
OXICLOUD_RUST_ASSETS unset (the default), that file is never written to
OUT_DIR, so a clean `cargo build` failed to compile. (#489)

Migrate the page off include_str! to an askama template
(templates/nextcloud/login.html), mirroring the existing
DrivePickerTemplate in the same handler. This drops the only
compile-time dependency on the legacy build.rs pipeline, so the
OXICLOUD_RUST_ASSETS=1 CI workaround is no longer needed and is removed
from ci.yml, load-smoke.yml and load-nightly.yml.

Also fix the second failure on #489: with OXICLOUD_RUST_ASSETS=1 the
release pipeline panicked in copy_dir_recursive because `static/locales`
is now a symlink to frontend/static/locales. entry.file_type() reports
the link itself (not its target), so the symlinked directory was routed
to fs::copy and failed with "the source path is neither a regular file
nor a symlink to a regular file". Classify entries with fs::metadata,
which follows symlinks, so symlinked directories are traversed.

static/nextcloud-login.html is removed (its content moved into the
template; no other consumer) and dropped from build.rs HTML_INCLUDE.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CNCEMN6fC2xSmxqCVbstkd

src/interfaces/nextcloud/login_v2_handler.rs

@@ -29,6 +29,14 @@ struct DrivePickerTemplate {
     drives: Vec<DriveOption>,
 }
 
+/// The Nextcloud Login Flow v2 "Grant Access" page. Rendered server-side via
+/// askama (no template variables — the username/password are collected by the
+/// embedded form) instead of `include_str!` so the build no longer depends on
+/// the legacy `build.rs` static-asset pipeline / `OUT_DIR`.
+#[derive(Template)]
+#[template(path = "nextcloud/login.html")]
+struct NextcloudLoginTemplate;
+
 // Home identification is via `position_of_user_home_root_folder` from
 // `domain::repositories::drive_repository` — a generic helper that
 // keys off `drives.default_for_user == user_id` rather than folder
@@ -36,7 +44,7 @@ struct DrivePickerTemplate {
 // picker UX.
 
 /// Serve an HTML page with a Content-Security-Policy header as defense-in-depth.
-fn html_with_csp(html: &'static str) -> Response {
+fn html_with_csp(html: String) -> Response {
     (
         [(
             header::CONTENT_SECURITY_POLICY,
@@ -160,10 +168,13 @@ pub async fn handle_login_page(
         return StatusCode::NOT_FOUND.into_response();
     }
 
-    html_with_csp(include_str!(concat!(
-        env!("OUT_DIR"),
-        "/nextcloud-login.html"
-    )))
+    match NextcloudLoginTemplate.render() {
+        Ok(html) => html_with_csp(html),
+        Err(e) => {
+            tracing::error!(error = %e, "Login Flow v2: login page template render failed");
+            StatusCode::INTERNAL_SERVER_ERROR.into_response()
+        }
+    }
 }
 
 pub async fn handle_login_submit(