compliance: flag-gate AI portfolio + cloud sync + Stripe; de-risk prompts; harden reviewer

Implements docs/read-markets-compliance-changes.md as flag-gated changes
(no deletions) so paused features stay in the tree for future re-enable.
All four flags default False so a fresh deploy is compliance-safe.

- New env flags: PORTFOLIO_AI_ENABLED, PORTFOLIO_SYNC_ENABLED,
  TICKER_UNIVERSE_AGGREGATE_ENABLED, SUBSCRIPTIONS_ENABLED.
- Gates: /api/analyze, /api/portfolio/sync*, /api/stripe/*, /pricing,
  ticker_universe writes, portfolio_analysis.analyse(). is_paid_active()
  returns True for any auth'd user when subscriptions are paused.
- Prompts (PROMPT_VERSION 10): universal _COMPLIANCE_RIDER prepended to
  every system prompt; watch list removed; price-target / close-above-below
  / trigger / forward-state-as-description rules added; SPECULATIVE
  pivoted to regime-only scenarios; daily + weekly digests tightened.
- Reviewer: deterministic regex/lexicon pre-check fail-closed under the
  Haiku call; portfolio rider gated by PORTFOLIO_AI_ENABLED; base prompt
  sharpened for forward-state and MAR forward-opinion patterns;
  ReviewerVerdict audit table; generate_with_review retry helper.
- Migration 0026: purge portfolio_sync + ticker_universe; create
  reviewer_verdicts.
- Copy: MAR cite fixed to Art 3(1)(35) + Art 20 + Del Reg 2016/958;
  portfolio reframed as browser-only viewer in disclaimer / privacy /
  terms / about / pricing / landing (en + it). TODO(legal) marker for
  lawyer sign-off on disclaimer.
- Tests: 13 lexicon + 6 reviewer compliance regressions; conftest enables
  all flags so existing 402 tests still cover their code paths.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/services/ticker_universe.py

@@ -33,6 +33,7 @@ from sqlalchemy import delete, insert, select, update
 from sqlalchemy.dialects.mysql import insert as mysql_insert
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from app.config import get_settings
 from app.db import utcnow
 from app.logging import get_logger
 from app.models import TickerUniverse
@@ -81,6 +82,8 @@ async def buffer_tickers(tickers: Iterable[str]) -> int:
 
     Already-known tickers are still buffered — the flush job will collapse
     them via INSERT IGNORE. Cheap and avoids a synchronous DB read here."""
+    if not get_settings().TICKER_UNIVERSE_AGGREGATE_ENABLED:
+        return 0
     items = [_normalise(t) for t in tickers if t and t.strip()]
     if not items:
         return 0
@@ -98,6 +101,8 @@ async def refresh_references(
     """Bump last_referenced_at for tickers already in the universe.
     Returns rows updated. Tickers not yet in the universe are silently
     ignored — they'll land via the buffered flush path."""
+    if not get_settings().TICKER_UNIVERSE_AGGREGATE_ENABLED:
+        return 0
     items = list({_normalise(t) for t in tickers if t and t.strip()})
     if not items:
         return 0
@@ -117,6 +122,8 @@ async def flush_buffer(session: AsyncSession) -> dict[str, int]:
 
     Idempotent: re-running on the same bucket is a no-op because the bucket
     is deleted on success."""
+    if not get_settings().TICKER_UNIVERSE_AGGREGATE_ENABLED:
+        return {"buffered": 0, "inserted": 0}
     r = get_redis()
     key = _previous_bucket_key()
     tickers = await r.smembers(key)
@@ -177,6 +184,8 @@ async def upsert_tickers(session: AsyncSession, tickers: Iterable[str]) -> int:
     mitigation has no statistical effect anyway, so bypassing it is free.
     When we hit ≥10 users this path will be deprecated in favour of the
     buffered path, per the Phase G plan."""
+    if not get_settings().TICKER_UNIVERSE_AGGREGATE_ENABLED:
+        return 0
     items = list({_normalise(t) for t in tickers if t and t.strip()})
     if not items:
         return 0