Convert main to README-only branch, update usage to reference @restore and @save branches

README.md

@@ -3,6 +3,13 @@ Cache Action
 
 A Gitea Action that caches build files as `tar.xz` archives on the runner filesystem. Simple, fast, no external dependencies.
 
+## Branches
+
+| Branch | Purpose |
+|--------|---------|
+| `restore` | Restores cache archive if it exists |
+| `save` | Saves cache archive (use after build) |
+
 ## Inputs
 
 | Input | Description | Required | Default |
@@ -15,20 +22,20 @@ A Gitea Action that caches build files as `tar.xz` archives on the runner filesy
 
 | Output | Description |
 |--------|-------------|
-| `cache-hit` | `true` if exact key match found, `false` otherwise |
+| `cache-hit` | `true` if exact key match found, `false` otherwise (restore only) |
 
 ## How It Works
 
 1. Hashes `key-file` with SHA-256, combines with `key-prefix` as `<prefix>-<hash>`
 2. Stores archives at `~/.cache/.cache-store/<key>.tar.xz`
-3. Restores by extracting the archive to `/`, saves by creating one
+3. `restore` branch extracts the archive, `save` branch creates one
 
 ## Usage
 
 This action must be used **twice** in your workflow:
 
-1. **Before build** — restores cache if it exists
-2. **After build** — saves the cache archive (only on cache miss)
+1. **Before build** — use `@restore` to restore cache if it exists
+2. **After build** — use `@save` to save the cache archive
 
 ## Rust Example
 
@@ -47,7 +54,7 @@ jobs:
       - uses: actions/checkout@v4
 
       # 1. Restore cache before build
-      - uses: Actions/Cache@main
+      - uses: Actions/Cache@restore
         id: cache
         with:
           key-prefix: 'cargo-registry'
@@ -58,7 +65,7 @@ jobs:
         run: cargo build --release
 
       # 2. Save cache after build
-      - uses: Actions/Cache@main
+      - uses: Actions/Cache@save
         with:
           key-prefix: 'cargo-registry'
           key-file: 'Cargo.lock'
@@ -82,7 +89,7 @@ jobs:
       - uses: actions/checkout@v4
 
       # 1. Restore cache
-      - uses: Actions/Cache@main
+      - uses: Actions/Cache@restore
         id: cache
         with:
           key-prefix: 'rust'
@@ -97,7 +104,7 @@ jobs:
         run: cargo build --release
 
       # 2. Save cache
-      - uses: Actions/Cache@main
+      - uses: Actions/Cache@save
         with:
           key-prefix: 'rust'
           key-file: 'Cargo.lock'