feat(ui): render dependency-chain rail, step badge, and after-chip in TaskRowView

Reuses the existing 24px indent track (now gated on ShowAsChild OR
ShowAsChainMember) instead of a second mechanism, adds a round step-number
badge centered on the rail line, and a dimmed "after X" chip for chain
members whose head isn't in view or that render as a planning child.

src/ClaudeDo.Localization/locales/de.json

@@ -163,6 +163,7 @@
     "badgeDraft": "ENTWURF",
     "badgePlanned": "GEPLANT",
     "badgeManual": "MANUELL",
+    "chainAfterPrefix": "nach",
     "manualTip": "Manuelle Erinnerung — Claude nimmt sie nie auf",
     "ctxMarkManual": "Als manuell markieren",
     "ctxMarkClaudeTask": "Als Claude-Aufgabe markieren",

src/ClaudeDo.Localization/locales/en.json

@@ -163,6 +163,7 @@
     "badgeDraft": "DRAFT",
     "badgePlanned": "PLANNED",
     "badgeManual": "MANUAL",
+    "chainAfterPrefix": "after",
     "manualTip": "Manual reminder — Claude never picks this up",
     "ctxMarkManual": "Mark as manual",
     "ctxMarkClaudeTask": "Mark as Claude task",