feat(bigmind): profile image + AI image gallery (schema v8)

- web.py: add /profile-image route (serves most-recent gallery PNG)
  add /gallery/image/<filename> route (per-image serving)
  add /gallery route (renders gallery page from DB)
  add _get_profile_image_path() helper
- web_render.py: replace emoji avatar with <img src=/profile-image>
  onerror fallback to 🧠 emoji
  add .nav bar with Profile/Gallery links to both pages
  add _render_gallery_html() full gallery page renderer
  add gallery CSS: .gal-grid, .gal-card, .gal-img, .gal-info, etc.
- db.py: bump SCHEMA_VERSION 7→8
  add gallery_images table (id, filename, prompt, tags, model,
    created_at, width, height, file_size_bytes)
  add _migrate_v7_to_v8() migration function
  add init_db() hook for v<8 migration
- tests: update test_schema_version_is_7→8 in test_db.py and
  test_feature7_live_sessions.py; add gallery_images to expected tables

Storage strategy: Option B (filesystem + DB metadata)
Images in ~/.mcp/bigmind/gallery/, metadata in SQLite
Pre-populated with 5 lumen_profiles images (seeds 2409122067,
764633840, 1367851518, 3135233944, 568659042)

Tests: 297/297 passing

mcp/bigmind/tests/test_db.py

@@ -8,18 +8,19 @@ class TestDbInit:
     def test_db_file_created(self, temp_db):
         assert temp_db.exists()
 
-    def test_schema_version_is_7(self, temp_db):
+    def test_schema_version_is_8(self, temp_db):
         conn = get_connection()
         row = conn.execute("SELECT version FROM schema_version").fetchone()
         conn.close()
         assert row is not None
-        assert row["version"] == 7
+        assert row["version"] == 8
 
     def test_all_tables_exist(self, temp_db):
         expected = {
             "users", "identity_profile", "sessions",
             "session_summaries", "conversation_chunks", "facts",
             "global_knowledge", "hypotheses", "upgrade_requests",
+            "gallery_images",
         }
         conn = get_connection()
         rows = conn.execute(

mcp/bigmind/tests/test_feature7_live_sessions.py

@@ -201,12 +201,12 @@ class TestSchemaV6:
             count = conn.execute("SELECT COUNT(*) FROM token_saves").fetchone()[0]
         assert count == 0  # table exists, just empty
 
-    def test_schema_version_is_7(self, temp_db):
+    def test_schema_version_is_8(self, temp_db):
         with db() as conn:
             version = conn.execute(
                 "SELECT version FROM schema_version"
             ).fetchone()["version"]
-        assert version == 7
+        assert version == 8
 
 
 # ── Token Efficiency Tracker (Feature 6) ──────────────────────────────────────