feat: add task management CLI and improve activity curation

- Add task store with dependency tracking and CLI (packages/server/src/tasks/)
- Extract principal param logic to shared util for server/app reuse
- Improve activity curator: collapse timeline, dedupe tool calls, simpler output
- Add MessageInput ref for focus control after agent cancel
- Include recent activity in wait timeout messages

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

.tasks/0c32789c.md

@@ -0,0 +1,9 @@
+---
+id: 0c32789c
+title: Add three random numbers
+status: open
+deps: [2769910f, 7018be3f, 537563b5]
+created: 2026-01-07T16:32:47.905Z
+---
+
+Epic: We will add three random numbers together. Task 1 picks a number, Task 2 adds another, Task 3 adds a third and reports the final sum.

.tasks/2769910f.md

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+---
+id: 2769910f
+title: Pick first random number
+status: done
+deps: []
+created: 2026-01-07T16:32:56.827Z
+---
+
+Pick a random number between 1-100. Record it in your notes as 'Number: X'. This is the starting value.
+
+## Notes
+
+**2026-01-07T16:33:43.884Z**
+
+Number: 47

.tasks/537563b5.md

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+---
+id: 537563b5
+title: Add third random number and report final sum
+status: done
+deps: [7018be3f]
+created: 2026-01-07T16:32:57.495Z
+---
+
+Pick a final random number between 1-100. Read previous notes to get the running total. Add your number. Record in notes: 'Added: X, FINAL SUM: Y'
+
+## Notes
+
+**2026-01-07T16:34:56.240Z**
+
+Added: 42, FINAL SUM: 112

.tasks/7018be3f.md

@@ -0,0 +1,15 @@
+---
+id: 7018be3f
+title: Add second random number
+status: done
+deps: [2769910f]
+created: 2026-01-07T16:32:57.142Z
+---
+
+Pick another random number between 1-100. Read the previous task's notes to get the running total. Add your number to it. Record in notes: 'Added: X, Running total: Y'
+
+## Notes
+
+**2026-01-07T16:34:17.347Z**
+
+Added: 23, Running total: 70