refactor: replace emoji status glyphs with ASCII tokens (#37)

Eyrie returns user-facing strings that hawk pipes straight to the
terminal (FormatPreflightReport, Report.Markdown) or to a markdown
viewer (GetModelDeprecationWarning). These three functions previously
embedded "✓", "✗", and "⚠" (U+2713 / U+2717 / U+26A0) — all in
the dingbats / symbol block, which the hawk audit test (added in
the parallel hawk commit) classifies as emoji.

Replacing them with ASCII tokens ("+", "x", "[warn]") makes the output
terminal-portable and keeps the no-emoji rule consistent across both
repos. Existing tests continue to pass:

  - runtime/preflight_test.go's "warn icon" case asserts the substring
    "!", which the warn branch still emits.
  - verify/verify_test.go's TestReport_Markdown asserts on the table
    header / detail columns, not the status cell.
  - catalog/deprecation_test.go asserts on the "will be retired on"
    substring.

The change is contained to three call sites; the data shape of
PreflightCheck, Report, and DeprecationEntry is untouched.

Author: Patel230

catalog/deprecation.go

@@ -35,7 +35,7 @@ func GetModelDeprecationWarning(modelID, provider string) string {
 		if !strings.Contains(canonical, key) || !ok || date == "" {
 			continue
 		}
-		return fmt.Sprintf("⚠ %s will be retired on %s. Consider switching to a newer model.", entry.ModelName, date)
+		return fmt.Sprintf("[warn] %s will be retired on %s. Consider switching to a newer model.", entry.ModelName, date)
 	}
 	return ""
 }

runtime/preflight.go

@@ -159,12 +159,12 @@ func FormatPreflightReport(r PreflightReport) string {
 		b.WriteString("Preflight: setup incomplete\n")
 	}
 	for _, c := range r.Checks {
-		icon := "✓"
+		icon := "+"
 		switch c.Status {
 		case PreflightWarn:
 			icon = "!"
 		case PreflightFail:
-			icon = "✗"
+			icon = "x"
 		}
 		fmt.Fprintf(&b, "  %s %s: %s\n", icon, c.Name, c.Detail)
 	}

verify/verify.go

@@ -194,10 +194,10 @@ func (r Report) Markdown() string {
 	out += fmt.Sprintf("- tool_call_f1: %.2f\n\n", r.F1Score)
 	out += "| case | result | latency | detail |\n|---|---|---|---|\n"
 	for _, c := range r.Results {
-		status := "✓"
+		status := "+"
 		detail := ""
 		if !c.Passed {
-			status = "✗"
+			status = "x"
 			detail = strings.Join(c.Failures, "; ")
 		}
 		out += fmt.Sprintf("| %s | %s | %s | %s |\n", c.ID, status, c.Latency.Round(time.Millisecond), detail)