feat: lazysecrets list prints everything lazysecrets can find, for fzf and editor pickers (#70)

`lazysecrets list` prints every source, vault and secret lazysecrets can find, one per line, for fzf, editor pickers and scripts: what Go to searches, without the TUI. What's cached prints at once; what's missing or older than `--max-age` loads in the background and streams in. It stops when the reader goes (a pick in fzf), saving what it loaded.

- Text: kind, mark (✗/⚠, ★, ◷ and the provider icon), name, status (why it couldn't be read, or expired / expires in 12d), note, account and link, tab-separated; kind first and account and link last, so new fields go between. Coloured from the theme; `--color never`, `--icons=false`, `--stars=false`, `--recent`, `--notes=false`, `--expiry=false`.
- `--format json`: an object per line, with starred, recent, lastUsed and uses, expires, enabled, note, reference and url too.
- `--kind` lists only some kinds, and doesn't load lists only other kinds need; `--cached` loads nothing.
- `lazysecrets open --action go|copy|show` skips the "what to do" menu and ends in the list, like Go to; `open` and `get` take `--account`, the account list printed, rather than asking which.
- The cache file moved to `internal/cachefile`: saves merge with the file under a lock, so list and the TUI don't undo each other.
- `ui.recentIcon` marks items used lately with ◷ in the TUI's lists too; Recent now means the last 90 days.
- --demo has stars, notes, recent use, and expired, expiring and disabled secrets.
- docs/integration.md documents get, list and an fzf picker; docs/links.md is docs/sharing.md.

Reviewed-on: #70
Co-authored-by: Karl-Einar Bergstrøm <karl-einarb@outlook.com>

internal/ui/app/expiring.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"slices"
 
+	"git.kebcloud.no/keb/lazysecrets/internal/cachefile"
 	"git.kebcloud.no/keb/lazysecrets/internal/provider"
 	"git.kebcloud.no/keb/lazysecrets/internal/ref"
 	"git.kebcloud.no/keb/lazysecrets/internal/ui/panes"
@@ -28,7 +29,7 @@ func (m Model) expiringItems() []expiringItem {
 			row := sourceRowKey(p.ID(), src.ID)
 			for _, c := range m.cache.containers[row].value {
 				for _, t := range c.ObjectTypes() {
-					for _, o := range m.cache.objects[containerKey(c)+"|"+string(t)].value {
+					for _, o := range m.cache.objects[cachefile.ObjectsKey(c, t)].value {
 						if state, _ := m.expiry(o); state != notExpiring {
 							out = append(out, expiringItem{o, row})
 						}