Register native sync providers for Excel, Google Calendar, and Outlook #3903

Summary

Register native memory-sync providers for the connectable-but-unsynced toolkits — Excel, Google Calendar, Outlook — by implementing IncrementalSource primitives for each so they ride run_sync and inherit max_items + the sync_depth_days window for free. This is the "every future toolkit gets caps + window automatically" promise of #3333 made concrete.

Problem / Context

These toolkits can be connected, but they have no native sync provider, so a sync attempt hits "no native memory sync provider registered" at composio/mod.rs:149 and ingests nothing. With the orchestrator in place, adding a provider is implementing ~5 small primitives instead of a full sync loop.

Scope

In scope

• Implement IncrementalSource (preamble, fetch_page, item_dedup_key, item_sort_ts, ingest, plus the relevant hooks) + a registry entry for excel, googlecalendar, outlook.
• A cap/window e2e for at least one of them via the shared orchestrator path.

Out of scope / notes

• Net-new orchestrator changes should not be required (use existing hooks); if one is, call it out.
• The backend toolkitFromSlug splitting at the first _ is a known separate bug (tinyhumansai/backend) — flag it if it blocks any of these slugs (e.g. google_calendar).

Acceptance criteria

• Excel — IncrementalSource impl + registry entry.
• Google Calendar — IncrementalSource impl + registry entry.
• Outlook — IncrementalSource impl + registry entry.
• No more unregistered error — none of the three hit "no native memory sync provider registered" (composio/mod.rs:149).
• Cap/window e2e — at least one of the three proves max_items + sync_depth_days via the shared path.
• Diff coverage ≥ 80% — the implementing PR meets the changed-lines coverage gate.

Related

• Parent: Generic Composio sync orchestrator so every toolkit enforces max_items and sync_depth_days #3333
• Depends on the orchestrator (refactor(memory_sync): generic Composio sync orchestrator + convert Notion (Refs #3333) #3852) being available.