feat(memory-sync): migrate Notion/ClickUp/Linear/GitHub Composio providers off UnifiedMemory

[justinhsu1477]

Summary

While auditing the #2705 silent-failure root cause for #2720, I noticed the same architectural pattern — provider writes to the legacy UnifiedMemory backend, retrieval reads from memory_tree — repeated across four native Composio providers. Slack and Gmail were already migrated; the remaining four were not.

Audit findings

`grep` over `src/openhuman/memory_sync/composio/providers/`:

Provider	Ingest path	Backend written
Slack	`ingest_pipeline::ingest_chat`	✅ memory_tree (`mem_tree_chunks`)
Gmail	`ingest_pipeline::ingest_email`	✅ memory_tree
Notion	`persist_single_item` → `store_skill_sync`	❌ UnifiedMemory (`memory_docs`)
ClickUp	`persist_single_item` → `store_skill_sync`	❌ UnifiedMemory
Linear	`persist_single_item` → `store_skill_sync`	❌ UnifiedMemory
GitHub	`persist_single_item` → `store_skill_sync`	❌ UnifiedMemory

Why this matters

Same symptom as #2705 but for Composio rather than vault:

• Synced Notion / ClickUp / Linear / GitHub items don't appear in `mem_tree_chunks` or `mem_tree_ingested_sources`.
• Every modern retrieval surface (`memory.search`, `tree.read_chunk`, `tree.browse`, the agent's recall path, summary trees, `tree.top_entities`) reads from memory_tree — so this data is invisible to all of them.
• Claude Desktop / Cursor / any MCP client doing `memory.search` against the user's OpenHuman gets zero Notion / ClickUp / Linear / GitHub hits even when the user has those toolkits connected.
• The legacy `UnifiedMemory::list_documents` / `query_namespace` API still surfaces the data for callers that use it directly, so this is a partial desync — less catastrophic than v0.54.0 — Vault sync UI shows "synced" but mem_tree_chunks and mem_tree_ingested_sources stay at 0 #2705's full-empty case, but still wrong.

Fix shape

Per provider:

1. Add a new `providers//ingest.rs` module that mirrors the Slack canonical pattern:
   • Single `ingest_into_memory_tree(config, owner, connection_id, item)` async function
   • Routes through `memory::ingest_pipeline::ingest_document` with a stable `source_id = "{toolkit}:{connection_id}:{item_id}"`
2. Update the provider's `sync()` to call the new `ingest_*` instead of `persist_single_item`.
3. `source_id` is the dedup key for memory_tree's append-only invariant; re-sync of unchanged items short-circuits via the pipeline's `already_ingested` gate, mirroring how Slack handles re-paged messages.
4. For each provider, add a regression test that pins the invariant: "a single sync of N items ⇒ N rows in `mem_tree_ingested_sources` and ≥N rows in `mem_tree_chunks`."

PR sequence

• Notion — reference implementation (smallest provider at 383 lines, senamakel's original code)
• GitHub — my feat(composio): promote GitHub from catalog-only to native memory provider #2413, smaller of the three I introduced
• Linear — my feat(composio): add Linear provider for Memory Tree ingest #2402
• ClickUp — my feat(composio): add ClickUp provider for Memory Tree ingest #2291 (largest, leaves for last after pattern is settled)

Each PR is independent and can be reviewed / merged separately. I'll handle all four.

Out of scope

• Removing `persist_single_item` / `store_skill_sync` entirely — those are senamakel's refactor(memory): separate tree policy from generic engine + E2E tests #2585 follow-up ("Consider removing `UnifiedMemory` legacy type"). This issue is scoped to migrating the read side; the legacy helpers stay for any non-Composio caller until the broader removal.
• Reconciling old `memory_docs`-only data already synced into UnifiedMemory — separate question, depends on retention story.

Refs

• v0.54.0 — Vault sync UI shows "synced" but mem_tree_chunks and mem_tree_ingested_sources stay at 0 #2705 / fix(vault): sync writes to memory_tree, not legacy UnifiedMemory (#2705) #2720 (vault sync) — same architectural pattern, fixed there
• refactor(memory): separate tree policy from generic engine + E2E tests #2585 (Consider removing `UnifiedMemory` legacy type follow-up)
• feat(composio): incremental sync with per-item persistence for Gmail and Notion #519 (senamakel's original native provider work)
• feat(composio): add ClickUp provider for Memory Tree ingest #2291 / feat(composio): add Linear provider for Memory Tree ingest #2402 / feat(composio): promote GitHub from catalog-only to native memory provider #2413 — my provider PRs that introduced the buggy path

[justinhsu1477]

All four Composio providers are now migrated off UnifiedMemory onto the memory_tree ingest_pipeline — closing.

Provider	PR	Status
Notion	#2887	✅ merged
GitHub	#2889	✅ merged
Linear	#3018	✅ merged
ClickUp	#3080	✅ merged

Each now routes through ingest_pipeline::ingest_document → mem_tree_chunks (with delete-first re-ingest cleanup + the is_source_ingested gate), so synced items are visible to memory.search / tree.* / MCP retrieval and the agent recall path. Thanks to everyone who picked up parts of the sequence.