fix(ci): replace continue-on-error with conditional step execution (#172)

Remove all continue-on-error usages from CI workflows:
- deploy.yml: replace continue-on-error on SSH deploy steps with
  if: secrets.SSH_PRIVATE_KEY != '' so steps are skipped (not failed)
  when the secret is absent
- windows-nightly.yml: remove continue-on-error from job and steps
  (job is already disabled via if: false)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.forgejo/workflows/deploy.yml

@@ -102,11 +102,7 @@ jobs:
         run: scripts/setup_dagger_remote.sh
 
       - name: Build & Deploy APK to server
-        # continue-on-error: step requires SSH_PRIVATE_KEY secret; if unset the task
-        # precondition fails, but we don't want that to fail the whole job — the Play
-        # Store publish above already succeeded.  The overall job stays green even
-        # though this step shows as failed/orange in the UI.
-        continue-on-error: true
+        if: ${{ secrets.SSH_PRIVATE_KEY != '' }}
         env:
           SSH_PRIVATE_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
           SSH_USER: ${{ secrets.SSH_USER }}
@@ -145,12 +141,7 @@ jobs:
         run: scripts/setup_dagger_remote.sh
 
       - name: Build & Deploy Linux to server
-        # continue-on-error: step requires SSH_PRIVATE_KEY secret; if unset the task
-        # precondition fails, but the build step that precedes this (done via Dagger)
-        # already succeeded.  Deployment is best-effort; a missing secret should not
-        # turn the job red.  The step will show as failed/orange in the UI even though
-        # the overall job is green — this is intentional.
-        continue-on-error: true
+        if: ${{ secrets.SSH_PRIVATE_KEY != '' }}
         env:
           SSH_PRIVATE_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
           SSH_USER: ${{ secrets.SSH_USER }}
@@ -191,9 +182,7 @@ jobs:
         run: scripts/setup_dagger_remote.sh
 
       - name: Generate build history and deploy website
-        # continue-on-error: website publish is best-effort; a missing SSH_PRIVATE_KEY
-        # should not block the overall workflow status.
-        continue-on-error: true
+        if: ${{ secrets.SSH_PRIVATE_KEY != '' }}
         env:
           SSH_PRIVATE_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
           SSH_USER: ${{ secrets.SSH_USER }}

.forgejo/workflows/windows-nightly.yml

@@ -11,7 +11,6 @@ jobs:
     name: Build & Deploy Windows (Nightly)
     runs-on: windows-runner
     if: false
-    continue-on-error: true
 
     steps:
       - uses: actions/checkout@v4
@@ -32,7 +31,6 @@ jobs:
 
       - name: Set up SSH key
         if: env.SKIP_BUILD != 'true'
-        continue-on-error: true
         env:
           SSH_PRIVATE_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
         run: |
@@ -42,7 +40,6 @@ jobs:
 
       - name: Deploy Windows to server
         if: env.SKIP_BUILD != 'true'
-        continue-on-error: true
         env:
           SSH_USER: ${{ secrets.SSH_USER }}
           SSH_HOST: ${{ secrets.SSH_HOST }}