email-activity agent: propose -> review -> approve grid notes (v0.1.0:64)

When a sent/received email is matched to an investor, a local-model agent drafts a
one-line dated note and queues it as a PENDING proposal (it never writes the grid
itself). On the Email Capture page a partner sees "Proposed grid notes", can edit the
text, and Approve (appends to that investor's grid notes cell, newest at bottom,
stamped with the approver) or Dismiss. Going-forward only: a cutoff (app_settings
email_activity_since, set on first run) means email dated before the feature was
enabled is never summarized, so the historical backfill makes no noise. Sovereign:
summaries run entirely on the local model (no redaction needed). Gmail sync interval
tightened 180 -> 15 min so outgoing email surfaces quickly.

Backend: migration 0002 (email_activity_proposals); propose_email_activity_notes()
runs via a new scheduler post_sync hook; list/decide functions + routes
GET /api/activity/proposals, POST .../{id}/approve|dismiss. Grid append stamps the
approving user (fundraising_state.updated_by has a FK to users). Test
test_email_activity.py (propose cutoff/idempotency, approve appends + edited note,
dismiss, already-decided guard) under FK enforcement.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/email_integration/migrations/0002_email_activity.sql

@@ -0,0 +1,26 @@
+-- ============================================================================
+-- email_activity_proposals — the email-activity agent's PROPOSED grid notes,
+-- queued for human review. The agent (local model, sovereign) drafts one note per
+-- newly-matched email; a partner approves (optionally after editing) or dismisses
+-- it in the web UI. Only on approval does the text get appended to the grid.
+-- One proposal per email (email_id UNIQUE) — never re-proposed.
+-- ============================================================================
+CREATE TABLE IF NOT EXISTS email_activity_proposals (
+    id            TEXT PRIMARY KEY,
+    email_id      TEXT NOT NULL UNIQUE,
+    investor_id   TEXT,                 -- fundraising_investors.id / grid row id (best-effort)
+    investor_name TEXT,
+    direction     TEXT,                 -- sent | received
+    summary       TEXT,                 -- the one-line gist from the local model
+    proposed_note TEXT,                 -- the full note as drafted (editable before approve)
+    email_subject TEXT,                 -- context shown to the reviewer
+    email_date    TEXT,
+    status        TEXT NOT NULL DEFAULT 'pending',  -- pending | approved | dismissed
+    decided_by    TEXT,                 -- users.id who approved/dismissed
+    decided_at    TEXT,
+    final_note    TEXT,                 -- the text actually appended on approval (may be edited)
+    created_at    TEXT DEFAULT (datetime('now')),
+    FOREIGN KEY(email_id) REFERENCES emails(id) ON DELETE CASCADE
+);
+CREATE INDEX IF NOT EXISTS idx_email_proposals_status ON email_activity_proposals(status);
+CREATE INDEX IF NOT EXISTS idx_email_proposals_investor ON email_activity_proposals(investor_id);