feat: the changelog in the status pane, built in (#12)

The status pane's rows (`0`, then `enter`) end with the changelog: every release up to the running one, newest first.

```
v0.2.0     2026-10-12
           added: Search with fzf's scoring and query syntax (#11) (65dc2d7)
           fixed: …
v0.1.0     2026-10-10
           Hello world 👋
```

- `CHANGELOG.md` is embedded at build time by a small root package (`changelog.go`, `package lazysecrets`, `//go:embed`), so it needs no network and matches the binary. `release.sh` updates the file before tagging, so a release's binary includes its own entry. `go install …@latest` gets it too, since the module includes the file.
- Entries show as text: links become `(#11) (65dc2d7)` (`update.PlainLinks`, shared with the `U` notes). `/` filters them like any Fields pane (`/fixed`, `/search`), and `y` copies one.
- `cliff.toml`: #11 was squash-merged with #10 (the status pane) in it, so a preprocessor rewrites its entry to name both. Otherwise the status pane would be missing from the changelog.

Test for the parsing: versions and dates, kinds, links as text, a release's own words, and the header and footer left out.

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

---------

Co-authored-by: Karl-Einar Bergstrøm <karl-einarb@outlook.com>
Reviewed-on: #12

internal/ui/app/app.go

@@ -75,6 +75,8 @@ type Options struct {
 	// and keeps its state, for the status pane.
 	ConfigFiles []string
 	StatePath   string
+	// Changelog is CHANGELOG.md, for the status pane.
+	Changelog string
 	// CacheFile keeps what was loaded between runs; "" keeps it for this
 	// run only.
 	CacheFile string
@@ -185,6 +187,7 @@ type Model struct {
 	configFiles []string
 	statePath   string
 	statusW     int // the status pane's width: the left column's, zoomed or not
+	changelog   []panes.Field
 	cacheDirty  bool
 	sourcesAt   map[string]time.Time
 	placeDir    string
@@ -448,7 +451,7 @@ func New(providers []provider.Provider, opts Options) Model {
 	m.spinning = true
 
 	m.cachePath, m.placeDir, m.sourcesAt = opts.CacheFile, opts.Dir, map[string]time.Time{}
-	m.configFiles, m.statePath = opts.ConfigFiles, opts.StatePath
+	m.configFiles, m.statePath, m.changelog = opts.ConfigFiles, opts.StatePath, changelogFields(opts.Changelog)
 	if m.cachePath != "" {
 		m.loadCacheFile()
 		if len(m.sourceResults) > 0 {