Add notification history with configurable persistence

[0xferrous]

wispd should retain a notification history so users can revisit past notifications after they leave
the live popup stack.

Desired behavior

• record every notification when it is received
• treat the live popup stack as just the current visible view
• keep history entries after notifications are dismissed, expired, closed, or replaced
• preserve the full replacement chain for notifications updated via replaces_id

Persistence / retention

History should support:

• in-memory retention
• optional on-disk persistence
• configurable retention/rotation-style limits, e.g.:
  • max entries
  • max age
  • max persisted size / rotated files

Scope

This issue is about the history m[]∙[] odel/storage/retention.

A future separate issue can cover a notification center / history browsing UI.

Likely implementation areas

• wisp-source: record history, track final state, handle pruning/persistence
• wisp-types: add history m[]∙[] etadata/types as needed
• debug/CLI path: expose history before a full UI exists

Acceptance criteria

• notifications remain available in history after leaving the live stack
• replacement chains are preserved
• retention is bounded/conf[]∙[] igurable
• persistence is configurable
• existing live notification behavior does not regress