feat: add prepare and publish composite actions

Add two focused subdirectory composite actions:

- prepare/action.yml: downloads the vociferate binary, runs it to update
  changelog and release-version, then commits, tags, and pushes — replacing
  the boilerplate git steps consumers previously had to write inline.

- publish/action.yml: extracts the matching changelog section and creates or
  updates the Gitea/GitHub release. Outputs release-id, tag, and version so
  consumers can upload their own assets after it runs.

Simplify the vociferate workflows to use ./prepare and ./publish directly,
validating both actions in the self-release pipeline.

Update README to show the clean two-action usage pattern.

README.md

@@ -81,24 +81,10 @@ If a release already exists for the same tag, the workflow updates its release n
 
 ## Reuse In Other Repositories
 
-You can reuse vociferate in two ways.
+Vociferate ships two composite actions that together cover the full release flow.
+Pin both to the same released tag.
 
-Use the composite action directly in your prepare workflow:
-
-```yaml
-- name: Prepare release files
-  uses: git.hrafn.xyz/aether/vociferate@v1.0.0
-  with:
-    version-file: internal/myapp/version/version.go
-    version-pattern: 'const Version = "([^"]+)"'
-    changelog: changelog.md
-```
-
-Set `version` only when you want to override the recommended version.
-Pin the composite action to a released tag. It downloads a prebuilt Linux binary from vociferate releases and caches it on the runner, so it does not require installing Go.
-For repositories using changelog-based versioning (the default), omit `version-file` and `version-pattern` entirely. Only set them for repositories that embed the version inside source code.
-
-A complete release setup should also split preparation from publication. For example:
+### `prepare` — update files, commit, and push tag
 
 ```yaml
 name: Prepare Release
@@ -118,26 +104,29 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: Prepare release files
-        id: prepare
-        uses: git.hrafn.xyz/aether/vociferate@v1.0.0
+      - uses: git.hrafn.xyz/aether/vociferate/prepare@v1.0.0
         with:
           version: ${{ inputs.version }}
-
-      - name: Commit and push prepared release
-        run: |
-          set -euo pipefail
-          tag="${{ steps.prepare.outputs.version }}"
-          git config user.name "gitea-actions[bot]"
-          git config user.email "gitea-actions[bot]@users.noreply.local"
-          git add changelog.md release-version
-          git commit -m "release: prepare ${tag}"
-          git tag "$tag"
-          git push origin HEAD
-          git push origin "$tag"
+          token: ${{ secrets.GITHUB_TOKEN }}
 ```
 
-Then use a separate tag workflow to publish the release from the tagged revision:
+Downloads a prebuilt vociferate binary, runs it to update `changelog.md` and
+`release-version`, then commits those changes to the default branch and pushes
+the release tag. Does not require Go on the runner.
+
+For repositories that embed the version inside source code, pass `version-file`
+and `version-pattern`:
+
+```yaml
+- uses: git.hrafn.xyz/aether/vociferate/prepare@v1.0.0
+  with:
+    version-file: internal/myapp/version/version.go
+    version-pattern: 'const Version = "([^"]+)"'
+    git-add-files: changelog.md internal/myapp/version/version.go
+    token: ${{ secrets.GITHUB_TOKEN }}
+```
+
+### `publish` — create release with changelog notes
 
 ```yaml
 name: Do Release
@@ -149,42 +138,33 @@ on:
 
 jobs:
   release:
-    uses: aether/vociferate/.gitea/workflows/do-release.yml@main
-    secrets: inherit
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: git.hrafn.xyz/aether/vociferate/publish@v1.0.0
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
 ```
 
-Call the reusable prepare workflow:
+Reads the matching section from `changelog.md` and creates or updates the
+Gitea/GitHub release with those notes. The `version` input is optional — when
+omitted it is derived from the current tag ref automatically.
+
+The `publish` action outputs `release-id` so you can upload additional release
+assets after it runs:
 
 ```yaml
-name: Prepare Release
+- id: publish
+  uses: git.hrafn.xyz/aether/vociferate/publish@v1.0.0
+  with:
+    token: ${{ secrets.GITHUB_TOKEN }}
 
-on:
-  workflow_dispatch:
-    inputs:
-      version:
-        description: Optional semantic version override.
-        required: false
-
-jobs:
-  release:
-    uses: aether/vociferate/.gitea/workflows/prepare-release.yml@main
-    with:
-      version: ${{ inputs.version }}
-    secrets: inherit
-```
-
-And publish from tags with:
-
-```yaml
-name: Do Release
-
-on:
-  push:
-    tags:
-      - "v*.*.*"
-
-jobs:
-  release:
-    uses: aether/vociferate/.gitea/workflows/do-release.yml@main
-    secrets: inherit
+- name: Upload my binary
+  run: |
+    curl --fail-with-body -X POST \
+      -H "Authorization: token ${{ secrets.GITHUB_TOKEN }}" \
+      -H "Content-Type: application/octet-stream" \
+      "${{ github.api_url }}/repos/${{ github.repository }}/releases/${{ steps.publish.outputs.release-id }}/assets?name=myapp" \
+      --data-binary "@dist/myapp"
 ```