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/email_integration/sync.py

@@ -23,6 +23,7 @@ import logging
 import sqlite3
 import traceback
 from typing import Optional
+from urllib.error import URLError
 
 from . import attachments as _attach
 from . import config as _cfg
@@ -112,6 +113,15 @@ def sync_account(conn_factory, credential_provider, account,
         error_str = "history expired; fallback to date backfill"
         status = "partial"
         _fallback_date_backfill(conn_factory, client, account, index, run_stats)
+    except (_errors.RateLimitError, _errors.TransientError, URLError, TimeoutError) as e:
+        # A network / 5xx / rate-limit error that outlived the in-pass retry loop.
+        # This is TRANSIENT, not terminal: park it as 'retrying' (which the scheduler
+        # still picks up every cycle) instead of 'error' (which it excludes). Fixes the
+        # v<=0.1.0:103 bug where a single timeout dark-listed a mailbox until a manual
+        # kick. Terminal causes (auth, permanent, unexpected) still fall through to 'error'.
+        error_str = f"transient: {type(e).__name__}: {e}"
+        status = "retrying"
+        log.warning("transient error during sync of %s: %s", email_addr, e)
     except Exception as e:
         error_str = f"unexpected: {type(e).__name__}: {e}"
         status = "error"