refactor: tidy up sharing after the round of tweaks

- Go to's picker settings are one picker struct, set while picking.
- Opening a share link plans the save, then asks or saves; no more
  offerWrite doing either by a flag.
- Closing the picker while it encrypts cancels the share, and a
  second pick meanwhile is ignored.
- Favourites and Recent leave out plain env values as keys too.
- share.key in the config is checked with share.ParseKey, so
  {{secrets/…}} is refused there already.
- A key that can't be read reads the same opening as sharing
  ("can't use …"); KeyError moved to share.go, maxFiles is
  maxUnpacked (bytes), and a stray comment is gone.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

internal/ui/app/sharefiles_test.go

@@ -15,6 +15,7 @@ import (
 	"git.kebcloud.no/keb/lazysecrets/internal/provider/fake"
 	"git.kebcloud.no/keb/lazysecrets/internal/provider/repo"
 	"git.kebcloud.no/keb/lazysecrets/internal/share"
+	"git.kebcloud.no/keb/lazysecrets/internal/store"
 )
 
 // scryptWait is how long the driver waits for encrypting and decrypting:
@@ -50,7 +51,7 @@ func shareFrom(t *testing.T, root string, paste bool) string {
 	// No share.key set: it asks which secret, in Go to, which lists
 	// only secrets.
 	v := d.m.search
-	if v == nil || v.pick == nil {
+	if v == nil || v.picker == nil {
 		t.Fatalf("no secret picker: %s", d.m.flash.text)
 	}
 	for _, o := range v.shown {
@@ -210,12 +211,12 @@ func TestShareInDemo(t *testing.T) {
 	}
 	src.Provider = "Repos"
 	d.run(d.m.shareFiles(src, nil))
-	if d.m.search == nil || d.m.search.pick == nil {
+	if d.m.search == nil || d.m.search.picker == nil {
 		t.Fatalf("no picker: %s", d.m.flash.text)
 	}
 	// Too short a key: the picker stays, saying why.
 	d.send(tea.PasteMsg{Content: "https://kv-app-prod.vault.azure.net/secrets/db-password"})
-	if d.m.search == nil || !strings.Contains(d.m.search.pickErr, "Can't use db-password: its value has 28 characters; share.keyRules needs 32 (minLength)") {
+	if d.m.search == nil || !strings.Contains(d.m.search.picker.err, "Can't use db-password: its value has 28 characters; share.keyRules needs 32 (minLength)") {
 		t.Fatalf("not said in the picker: %v\n%s", d.m.search != nil, d.screen())
 	}
 	if !strings.Contains(d.screen(), "28 characters") {
@@ -248,3 +249,66 @@ func TestShareInDemo(t *testing.T) {
 		t.Fatalf("nothing saved (%s)", d.m.flash.text)
 	}
 }
+
+func TestPickerCancelAndBusy(t *testing.T) {
+	clip := &fakeClipboard{}
+	d := newDriverOpts(t, Options{Clipboard: clip},
+		fake.Azure(0), fake.AzureOps(0).As("Azure:admin", "Azure · admin"), fake.Repos())
+	var src provider.Source
+	for _, s := range d.m.sourceResults["Repos"].sources {
+		if s.Here {
+			src = s
+		}
+	}
+	src.Provider = "Repos"
+	d.run(d.m.shareFiles(src, nil))
+	p := d.m.search.picker
+	key, _ := share.ParseKey("https://kv-shared-prod.vault.azure.net/secrets/env-share")
+
+	// Picking starts sealing; another pick meanwhile is ignored.
+	cmd := p.choose(&d.m, key)
+	if cmd == nil || p.busy == "" {
+		t.Fatal("picking didn't start")
+	}
+	if again := p.choose(&d.m, key); again != nil {
+		t.Error("a second pick while busy wasn't ignored")
+	}
+
+	// Closed before the link is made: cancelled, nothing copied.
+	d.m.search = nil
+	d.wait = scryptWait
+	d.run(cmd)
+	if clip.content != "" {
+		t.Errorf("copied after the picker was closed: %q", clip.content)
+	}
+}
+
+func TestPlainEnvNotPickableFromFavourites(t *testing.T) {
+	mem, _ := store.Load("")
+	d := newDriverOpts(t, Options{Store: mem}, fake.Azure(0), fake.Repos())
+	var src provider.Source
+	for _, s := range d.m.sourceResults["Repos"].sources {
+		if s.Here {
+			src = s
+		}
+	}
+	// A key in the demo repo's plain .env, starred.
+	key := "lazysecrets://repo/" + url.PathEscape(src.Detail) + "/.env/DATABASE_URL"
+	mem.Update(key, func(n *store.Node) {
+		n.StarredBy = []string{"Repos"}
+		n.Path = []string{src.Name, ".env"}
+		n.Source = src.ID
+	})
+	src.Provider = "Repos"
+	d.run(d.m.shareFiles(src, nil))
+	favs, _ := d.m.storeEntries()
+	for _, o := range favs {
+		if o.star == key {
+			if _, ok := pickable(o); ok {
+				t.Error("a plain .env value is offered as a key in Favourites")
+			}
+			return
+		}
+	}
+	t.Fatalf("the starred key isn't among the favourites: %d", len(favs))
+}