feat: link each changelog entry to its PR and commit (#11)

Like Immich's and RomM's release notes: every changelog entry now links to its pull request and its commit, in `CHANGELOG.md` and in the release notes on Gitea:

```
- Search with fzf's scoring and query syntax ([#11](…/pulls/11)) ([65dc2d7](…/commit/65dc2d7…))
```

- `cliff.toml`: the entry template adds the short commit hash as a link; a postprocessor turns the squash commit's `(#N)` into a link to the PR.
- The app shows release notes as text (`U`, and the status pane's changelog to come), so `Release.Notes()` turns Markdown links back into their text: `Search (#11) (65dc2d7)`.

Checked with `git cliff --unreleased` on main: every entry since v0.1.0 gets both links. Test for the link stripping.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Karl-Einar Bergstrøm <karl-einarb@outlook.com>
Reviewed-on: #11

internal/update/update.go

@@ -22,6 +22,7 @@ import (
 	"os/exec"
 	"path"
 	"path/filepath"
+	"regexp"
 	"runtime"
 	"strings"
 	"time"
@@ -49,9 +50,13 @@ type Release struct {
 // every release ends with.
 func (r Release) Notes() string {
 	notes, _, _ := strings.Cut(r.Body, "## Install")
-	return strings.TrimSpace(notes)
+	return mdLink.ReplaceAllString(strings.TrimSpace(notes), "$1")
 }
 
+// mdLink is a Markdown link, [text](url): the notes link PRs and commits,
+// and a terminal shows them as their text.
+var mdLink = regexp.MustCompile(`\[([^\]]+)\]\((https?://[^)\s]+)\)`)
+
 // Client talks to the release server.
 type Client struct {
 	API  string // the repository's API, DefaultAPI when empty

internal/update/update_test.go

@@ -123,3 +123,10 @@ func TestInstallRefusesATamperedArchive(t *testing.T) {
 		t.Error("replaced anyway")
 	}
 }
+
+func TestNotesShowLinksAsText(t *testing.T) {
+	r := Release{Body: "### Added\n\n- Search ([#11](https://git.example.com/pulls/11)) ([65dc2d7](https://git.example.com/commit/65dc2d7abc))\n\n## Install\n\ncurl …"}
+	if got, want := r.Notes(), "### Added\n\n- Search (#11) (65dc2d7)"; got != want {
+		t.Errorf("notes %q, want %q", got, want)
+	}
+}