Add TRS-80, RX-78, Sega AI entries; refactor tools

Add many MAME/MESS BIOS entries (TRS-80 family, Bandai RX-78, Sega AI) and update docs/navigation counts (README, mkdocs). Remove empty supplemental file references from database.json and update generated timestamps and totals. Harden and refactor tooling: add MAX_RESPONSE_SIZE limited reader in base_scraper, make target scrapers an abstract base, narrow exception handling in the Batocera targets parser, and switch generate_pack.py and verify.py to use build_target_cores_cache (simplifies target config loading and error handling). verify.py also loads supplemental cross-reference names and accepts them through verify_platform. Update tests to import from updated modules (validation/truth). Misc: small bugfix for case-insensitive path conflict check.

database.json

@@ -1,6 +1,6 @@
 {
-  "generated_at": "2026-03-29T20:52:06Z",
-  "total_files": 7245,
+  "generated_at": "2026-03-29T21:04:08Z",
+  "total_files": 7244,
   "total_size": 9715681216,
   "files": {
     "520d3d1b5897800af47f92efd2444a26b7a7dead": {
@@ -36133,16 +36133,6 @@
       "crc32": "c1815325",
       "adler32": "c48a690f"
     },
-    "da39a3ee5e6b4b0d3255bfef95601890afd80709": {
-      "path": "bios/NEC/PC-98/key.txt",
-      "name": "key.txt",
-      "size": 0,
-      "sha1": "da39a3ee5e6b4b0d3255bfef95601890afd80709",
-      "md5": "d41d8cd98f00b204e9800998ecf8427e",
-      "sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
-      "crc32": "00000000",
-      "adler32": "00000001"
-    },
     "3518193b8207bdebf22c1380c2db8c554baff329": {
       "path": "bios/NEC/PC-98/n88.rom",
       "name": "n88.rom",
@@ -76069,7 +76059,6 @@
       "38d32748ae49d1815b0614970849fd40": "78ba9960f135372825ab7244b5e4e73a810002ff",
       "8b52de9032ea62153dc783151306595f": "0877ffb4b4d1c18283468be3579b72ed8c22e3ac",
       "72ea51443070f0e9212bfc9b793ee28e": "a2fb11c000ed7c976520622cfb7940ed6ddc904e",
-      "d41d8cd98f00b204e9800998ecf8427e": "da39a3ee5e6b4b0d3255bfef95601890afd80709",
       "22be239bc0c4298bc0561252eed98633": "3518193b8207bdebf22c1380c2db8c554baff329",
       "e28fe3f520bea594350ea8fb00395370": "d1ae642aed4f0584eeb81ff50180db694e5101d4",
       "a8e298da7ac947669bcb1ff25cee0a83": "4ae4d37409ff99411a623da9f6a44192170a854e",
@@ -89999,9 +89988,6 @@
       "ide.rom": [
         "0877ffb4b4d1c18283468be3579b72ed8c22e3ac"
       ],
-      "key.txt": [
-        "da39a3ee5e6b4b0d3255bfef95601890afd80709"
-      ],
       "n88_1.rom": [
         "4ae4d37409ff99411a623da9f6a44192170a854e"
       ],
@@ -102454,9 +102440,6 @@
       "custom0.sf2": [
         "286b2e1fb21cc79851da01666db6c0b0e88f25e3"
       ],
-      "Custom.dat": [
-        "da39a3ee5e6b4b0d3255bfef95601890afd80709"
-      ],
       "tos106de.img": [
         "3b8cf5ffa41b252eb67f8824f94608fa4005d6dd"
       ],
@@ -107087,7 +107070,6 @@
       "456d9fc7": "78ba9960f135372825ab7244b5e4e73a810002ff",
       "d402842f": "0877ffb4b4d1c18283468be3579b72ed8c22e3ac",
       "c1815325": "a2fb11c000ed7c976520622cfb7940ed6ddc904e",
-      "00000000": "da39a3ee5e6b4b0d3255bfef95601890afd80709",
       "ffd68be0": "3518193b8207bdebf22c1380c2db8c554baff329",
       "61984bab": "d1ae642aed4f0584eeb81ff50180db694e5101d4",
       "7ad5d943": "4ae4d37409ff99411a623da9f6a44192170a854e",
@@ -127186,9 +127168,6 @@
       "zc210/sf2/custom0.sf2": [
         "286b2e1fb21cc79851da01666db6c0b0e88f25e3"
       ],
-      "zc210/sfx/Custom.dat": [
-        "da39a3ee5e6b4b0d3255bfef95601890afd80709"
-      ],
       "zc210/zcdata.dat": [
         "33b50cec88bc1569431a7885c0cc2692fddb004b"
       ]