Remove Instructions/Feedback + lp_profiles; sync retry, purge, mobile fixes (v0.1.0:104)

Removals (net -570 lines):
- Delete the Instructions and Feedback (feature_requests) pages + backend.
- Retire lp_profiles + investor_type across server, ingest, and seeds; migration
  0008 drops both empty tables (a sanctioned one-off exception to
  never-hard-delete). 0001's lp_profiles ALTER is removed so a fresh DB doesn't
  break the migration chain (live DBs already applied it).

Fixes:
- Email sync: a transient timeout no longer terminally parks a mailbox; the
  scheduler retries 'retrying' each cycle and re-includes errored accounts on an
  hourly backoff, so stuck mailboxes self-heal.
- Mobile Contacts: page through the full directory (server caps 500/page) -- one
  fetch silently truncated at 720, hiding people from the list and from search.
- Mobile email review: clock icon to set a reminder inline; approval cards show
  date/time.

New:
- Admin-only purge of soft-deleted rows (Settings -> Admin; type-to-confirm,
  refuses any row still linked to live data).

Tests: 45/45 (adds test_sync_ready + test_purge_soft_deleted). Reviewer pass
applied (NULL reminders.contact_id on contact purge). Bumped to v0.1.0:104.

backend/ingest/entity_resolution.py

@@ -8,7 +8,6 @@ layer created by migration 0001:
     fundraising_investors  ─┴─►  canonical_entities (entity_kind = lp | organization)
     contacts               ─┐
     fundraising_contacts   ─┴─►  canonical_entities (entity_kind = person)
-    lp_profiles            ───►  linked to its contact's person entity
 
 Every source row is recorded in `entity_links` so any name variant resolves to
 one canonical id. This is the DETERMINISTIC tier — it merges only what we can
@@ -184,7 +183,7 @@ def resolve_people(conn, org_canon_by_orgid, org_canon_by_fundinv, merge_map=Non
     people — each is matched to a contact-person and recorded only as a member_of
     edge to its investor entity (the grid's 'Contacts' column says who belongs to
     which investor). This is what stops the double-count.
-    Returns contact_id -> person canonical id (for lp_profiles)."""
+    Returns contact_id -> person canonical id."""
     merge_map = merge_map or {}
     contact_to_person = {}
     person_meta = {}
@@ -245,12 +244,6 @@ def resolve_people(conn, org_canon_by_orgid, org_canon_by_fundinv, merge_map=Non
             _link(conn, cid, "fundraising_contacts", r["id"], email or name_norm, mk, 0.95 if mk == "grid_link" else 0.9)
             _member_of(conn, cid, inv_canon)
 
-    # lp_profiles -> the person entity of its contact
-    for r in conn.execute("SELECT id, contact_id FROM lp_profiles WHERE deleted_at IS NULL"):
-        cid = contact_to_person.get(r["contact_id"])
-        if cid:
-            _link(conn, cid, "lp_profiles", r["id"], r["contact_id"], "contact_fk", 1.0)
-
     return person_meta