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>

README.md

@@ -12,10 +12,7 @@ A terminal UI for finding, reading and sharing secrets. Inspired by the fantasti
   CLI, `sops`, `git`). No config file needed.
 - **Search everything**: `ctrl+s` searches every source at once, with
   fzf-style matching.
-- **Share links**: Share `lazysecrets://` links with colleagues. A colleague opens it
-  with their own access, from the terminal or with a click in the browser
-  or chat. `.env` files can be shared too, as a link encrypted with a
-  secret your team can read.
+- **Share links**: Share `lazysecrets://` links with colleagues.
 - **Neovim integration**: via [lazysecrets.nvim](https://github.com/karleinarb/lazysecrets.nvim)
 - **Careful with values**: values stay hidden until you reveal them, and
   copied values are cleared from the clipboard after 30 seconds.
@@ -80,14 +77,32 @@ use most:
 | `?` | every key, searchable |
 | `q` | quit |
 
+
+## Integration
+Lazysecret let you integrate it into your workflows by `lazysecrets` `list`/`get`/`open`
+
+Here is an example of implementing a picker in `fzf`:
+```sh
+lazysecrets list | fzf --ansi --delimiter='\t' --with-nth='2..-3' --nth='2..' --accept-nth=-1 \
+  --header 'enter: link · ctrl-o: open · ctrl-y: copy value · ctrl-x: copy and close' \
+  --bind 'ctrl-o:become(lazysecrets open --action go --account {-2} {-1})' \
+  --bind 'ctrl-y:execute-silent(lazysecrets get --account {-2} {-1} | pbcopy)+change-header(Copied the value of {3})' \
+  --bind 'ctrl-x:become(lazysecrets get --account {-2} {-1} | pbcopy)'
+```
+
+![fzf-example](docs/assets/fzf-example.png)
+
+More defails in the [Integration](docs/integration.md) docs
+
 ## Docs
 
 - [Keys](docs/keys.md): every key, Go to, the layout, and rebinding keys
 - [Azure Key Vault](docs/azure.md): accounts, permissions, pinned vaults
 - [Databricks](docs/databricks.md): profiles and Key Vault-backed scopes
 - [SOPS and .env files](docs/repos.md): which repos and files, decrypting
-- [Links](docs/links.md): sharing, opening, `lazysecrets get` in scripts,
-  and opening links from the browser and chat
+- [Sharing](docs/sharing.md): links to secrets, encrypted env files, and
+  opening links, also from the browser and chat
+- [Integration](docs/integration.md): how lazysecrets can integrate into other systems
 - [Custom commands](docs/custom-commands.md): run your own commands on a
   secret
 - [Config](docs/config.md): every option, themes, layered configs, the