ci(delta-sync): raise password-only fixture timeout 15m -> 25m

The fallback-fixture job uses an isolated rust-cache shared-key
(delta-sync-fallback) that is invalidated whenever Cargo.lock churns
(deps-bump PRs from Dependabot, scheduled batch bumps, Tauri
ecosystem upgrades). On a cold cache the workspace + Tauri + aeroftp
lib compile takes 18-22 minutes before the integration test binary
links, which exceeds the previous 15m ceiling and silently cancels
the run.

The sibling key-auth lane fits comfortably in 11 minutes with a warm
default cache, so it stays at 15m. 25m on the fallback lane gives
enough headroom for cold-start runs without parking PRs forever.

Affects #168 and #169 which were both stuck on this timeout.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: axpnet

.github/workflows/delta-sync-integration.yml

@@ -134,7 +134,12 @@ jobs:
     # blocks the PR independently.
     name: SFTP password-only fixture + fallback contract
     runs-on: ubuntu-latest
-    timeout-minutes: 15
+    # Cold-cache PRs (Cargo.lock churn from deps bumps) compile the full
+    # workspace + Tauri + aeroftp lib before the test binary links. The
+    # sibling key-auth job needs ~11min on a warm shared cache; this lane
+    # uses an isolated shared-key so the first cache miss can take 18-22
+    # minutes. 25min gives enough headroom without parking PRs forever.
+    timeout-minutes: 25
 
     steps:
       - name: Checkout