feat(cli): add micasa status command for headless health checks (#930)

## Summary

- Add `micasa status [--json] [--days N] [database-path]` command for
non-TUI overdue/upcoming item checking
- Exit codes: 0 (nothing needs attention), 1 (error), 2 (items need
attention) — useful for cron jobs, shell prompts, status bar widgets
- Extract duration helpers from `dashboard.go`/`table.go` to
`internal/data/duration.go` (DRY)

## Reproduction steps

1. `micasa status` — text output showing overdue maintenance, open
incidents, active projects
2. `micasa status --json` — JSON output for scripting
3. `micasa status --days 7` — narrow look-ahead window
4. Check exit code: `micasa status; echo $?` — 0 if clean, 2 if items
need attention

## Changes

- `cmd/micasa/status.go` — cobra command with text/JSON rendering,
`--days`/`--json` flags
- `cmd/micasa/status_test.go` — 24 tests covering output formats, exit
codes, validation, sort order, error paths
- `cmd/micasa/main.go` — `exitError` sentinel type, `extractExitCode`,
custom fang error handler, command registration
- `internal/data/duration.go` — extracted `DateDiffDays`, `ShortDur`,
`DaysText`, `PastDur`
- `internal/data/duration_test.go` — duration helper unit tests (100%
coverage)
- `internal/app/dashboard.go` — delegates to `data.*` helpers
- `internal/app/table.go` — delegates `dateDiffDays` to
`data.DateDiffDays`
- `docs/content/docs/reference/cli.md` — regenerated CLI reference

Closes #692

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

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: cpcloud

cmd/micasa/main.go

@@ -78,11 +78,30 @@ func newRootCmd() *cobra.Command {
 		newQueryCmd(),
 		newGenCLIRefCmd(),
 		newDBCmd(),
+		newStatusCmd(),
 	)
 
 	return root
 }
 
+// exitError is a sentinel error that carries a process exit code.
+// It is not printed to stderr by the error handler.
+type exitError struct {
+	code int
+}
+
+func (e exitError) Error() string { return "" }
+
+// extractExitCode returns the exit code from an exitError, or 1 for
+// any other error.
+func extractExitCode(err error) int {
+	var ee exitError
+	if errors.As(err, &ee) {
+		return ee.code
+	}
+	return 1
+}
+
 func main() {
 	root := newRootCmd()
 	if err := fang.Execute(
@@ -91,11 +110,18 @@ func main() {
 		fang.WithVersion(versionString()),
 		fang.WithColorSchemeFunc(wongColorScheme),
 		fang.WithNotifySignal(os.Interrupt),
+		fang.WithErrorHandler(func(w io.Writer, _ fang.Styles, err error) {
+			var ee exitError
+			if errors.As(err, &ee) {
+				return
+			}
+			_, _ = fmt.Fprintln(w, err)
+		}),
 	); err != nil {
 		if errors.Is(err, tea.ErrInterrupted) {
 			os.Exit(130)
 		}
-		os.Exit(1)
+		os.Exit(extractExitCode(err))
 	}
 }