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/sync.py

@@ -34,7 +34,7 @@ import entity_resolution as er
 import qdrant_io
 
 _CHANGE_TABLES = [("communications", "communications"), ("contacts", "contacts"),
-                  ("lp_profiles", "lp_profiles"), ("opportunities", "opportunities"),
+                  ("opportunities", "opportunities"),
                   ("organizations", "organizations"), ("fundraising_investors", "fundraising_investors")]
 
 
@@ -63,7 +63,7 @@ def _state_set(conn, key, value):
 def _deleted_source_ids(conn, since):
     """CRM records soft-deleted since the watermark — their chunks get pruned."""
     ids = set()
-    for tbl in ("contacts", "organizations", "opportunities", "communications", "lp_profiles"):
+    for tbl in ("contacts", "organizations", "opportunities", "communications"):
         try:
             for r in conn.execute(f"SELECT id FROM {tbl} WHERE deleted_at IS NOT NULL AND deleted_at > ?", (since,)):
                 ids.add(r["id"])