Bump deprecated CI action pins and drop phantom develop branch references

.github/copilot-instructions.md

@@ -16,7 +16,7 @@ making any changes.
 
 - `src/main/java/com/github/backup/` – Core application classes (backup service, GitHub service, CLI runner)
 - `src/main/java/com/github/backup/web/` – Spring MVC REST controller and request/response models for web mode
-- `src/main/resources/` – `application.properties`, `application-web.properties`, and static web assets
+- `src/main/resources/` – `application.properties`, `application-web.properties`, `application-daemon.properties`, and static web assets
 - `src/test/java/` – Unit tests mirroring the main source tree
 
 ## Coding Conventions
@@ -28,6 +28,6 @@ making any changes.
 
 ## Contribution Workflow
 
-- Branch from `develop` for all changes.
-- Open a pull request against `develop`, not `main`.
+- Branch from `main` for all changes.
+- Open a pull request against `main`.
 - Reference the related GitHub issue in every pull request description.

.github/workflows/build.yml

@@ -2,9 +2,9 @@ name: Build
 
 on:
   push:
-    branches: [ main, develop ]
+    branches: [ main ]
   pull_request:
-    branches: [ main, develop ]
+    branches: [ main ]
 
 jobs:
   build:
@@ -13,10 +13,10 @@ jobs:
       contents: read
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - name: Set up JDK 17
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@v5
         with:
           java-version: '17'
           distribution: 'temurin'
@@ -30,7 +30,7 @@ jobs:
       contents: read
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - name: Test entrypoint script
         run: sh docker-entrypoint-test.sh

.github/workflows/release.yml

@@ -12,10 +12,10 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
 
       - name: Set up JDK 17
-        uses: actions/setup-java@v4
+        uses: actions/setup-java@v5
         with:
           java-version: '17'
           distribution: 'temurin'

CHANGELOG.md

@@ -11,9 +11,15 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - `BACKUP_INTERVAL_MS` environment variable for the Docker daemon image, mapped by `docker-entrypoint.sh` to `-Dbackup.scheduled.interval.ms`, so the backup interval can be configured from `.env`/`docker-compose.yml` without overriding the entrypoint
 - `docker-entrypoint-test.sh`, a shell test that runs `docker-entrypoint.sh` against a stub `java` and asserts the argument list built for each combination of `BACKUP_DIRECTORY`, `SCHEDULED_USERS` and `BACKUP_INTERVAL_MS`, including empty values and values containing spaces; it runs in the `docker-build` CI job, so entrypoint changes are no longer merged unexecuted
 
+### Changed
+
+- CI now pins `actions/checkout@v5` and `actions/setup-java@v5` in both `.github/workflows/build.yml` and `.github/workflows/release.yml`, replacing the `v4` pins that GitHub has deprecated along with the Node.js 20 runtime they target
+
 ### Fixed
 
 - Documentation accuracy: the `java -jar` examples in `README.md`, `USER_GUIDE.md` and `CONFIG.md` now name `target/gh-backup-2.0.0-SNAPSHOT-8-8-2026.jar`, the artifact the build actually produces, instead of the non-existent `target/gh-backup-1.0.0.jar`
+- The `Build` workflow no longer triggers on a `develop` branch, and `.github/copilot-instructions.md` no longer instructs contributors to branch from and open pull requests against `develop`; the repository has only ever had `main`, and `CONTRIBUTING.md` was corrected to match in an earlier change
+- `.github/copilot-instructions.md` now lists `application-daemon.properties` among the files under `src/main/resources/`, alongside `application.properties` and `application-web.properties`
 
 ## [2.0.0-SNAPSHOT-8-8-2026] – 2026-08-08