fix: DeepSeek niche/type not saving to DB

Two bugs:
1. _parse_classify_output stripped <think> block before searching for JSON.
   DeepSeek-R1 often puts the JSON array inside the think block (especially
   when it "decides" mid-reasoning), so stripping it first destroyed the data.
   Fix: search full output first, then inside <think>, then stripped — three
   fallback strategies with info logging at each step.

2. Phase 2 save used bare UPDATE WHERE domain=? which silently does nothing
   if the domain row doesn't exist yet in enriched_domains.
   Fix: replace with INSERT ... ON CONFLICT DO UPDATE (true upsert).

Also adds logger.info lines so container logs show raw DeepSeek output
and parse result count for easy debugging.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/db.py

@@ -436,10 +436,14 @@ async def save_prescreen_results(results: list[dict]):
             niche     = r.get("niche")
             site_type = r.get("type")   # DeepSeek returns "type" key
             if niche or site_type:
-                # Classification-only update (domain row must already exist)
+                # Upsert niche/type — works even if the row was never enriched
                 await db.execute(
-                    "UPDATE enriched_domains SET niche=?, site_type=? WHERE domain=?",
-                    (niche, site_type, domain),
+                    """INSERT INTO enriched_domains (domain, niche, site_type)
+                       VALUES (?, ?, ?)
+                       ON CONFLICT(domain) DO UPDATE SET
+                         niche=excluded.niche,
+                         site_type=excluded.site_type""",
+                    (domain, niche, site_type),
                 )
             else:
                 # Prescreen status upsert — create row if it doesn't exist yet