fix: unambiguous repo key names, clearer config and key names, and a newer lazysecrets's files no longer stop an older one (#66)

Changes that would break configs or links once people use lazysecrets, made while nobody does yet.

- **Repo key names**: a dot or bracket inside a key is escaped (`app\.name`), so links to it resolve to that key and not to `app` → `name`. Dotenv files are flat, so their names stay as they are.
- **Config**: `updates.updateSources` is now `updates.sources`. A negative provider timeout, or `--timeout` of 0 or less, is an error instead of making every request fail.
- **Keybindings**: `lists.share` is now `lists.copyLink`, `lists.search` is `lists.goTo` and `lists.enter` is `lists.open`, matching what they do.
- **Version skew**, e.g. a lazysecrets.nvim theme file made for a newer lazysecrets:
  - an unknown theme role is skipped with a warning instead of stopping startup;
  - a state file from a newer version is read but not saved to, with a warning;
  - a link with an unknown provider suggests `lazysecrets update`.

Reviewed-on: #66
Co-authored-by: Karl-Einar Bergstrøm <karl-einarb@outlook.com>

internal/ui/app/app.go

@@ -79,6 +79,9 @@ type Options struct {
 	// and keeps its state, for the status pane.
 	ConfigFiles []string
 	StatePath   string
+	// Warning shows when the window opens: what lazysecrets skipped
+	// instead of failing to start.
+	Warning string
 	// Changelog is CHANGELOG.md, for the status pane.
 	Changelog string
 	// CacheFile keeps what was loaded between runs; "" keeps it for this
@@ -474,6 +477,9 @@ func New(providers []provider.Provider, opts Options) Model {
 	m.cachePath, m.placeDir, m.sourcesAt = opts.CacheFile, opts.Dir, map[string]time.Time{}
 	m.shareKey, m.shareRules = opts.ShareKey, opts.ShareRules
 	m.configFiles, m.statePath, m.changelog = opts.ConfigFiles, opts.StatePath, changelogFields(opts.Changelog)
+	if opts.Warning != "" {
+		m.flash = warning(opts.Warning)
+	}
 	if m.cachePath != "" {
 		m.loadCacheFile()
 		if len(m.sourceResults) > 0 {