Move sqlite-vss to optionalDependencies, remove tree-sitter-liquid

sqlite-vss fails to compile on Windows — moving it to optional lets
install succeed while the code already falls back to brute-force
vector search. tree-sitter-liquid is removed entirely as it has ABI
incompatibility with tree-sitter 0.22+ and Liquid is handled by the
built-in regex extractor.

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

package.json

@@ -37,7 +37,6 @@
     "better-sqlite3": "^11.0.0",
     "commander": "^14.0.2",
     "figlet": "^1.8.0",
-    "sqlite-vss": "^0.1.2",
     "tree-sitter": "0.22.4",
     "tree-sitter-c": "0.23.4",
     "tree-sitter-c-sharp": "0.23.1",
@@ -47,7 +46,6 @@
     "tree-sitter-java": "0.23.5",
     "tree-sitter-javascript": "0.23.1",
     "tree-sitter-kotlin": "0.3.8",
-    "tree-sitter-liquid": "github:hankthetank27/tree-sitter-liquid",
     "tree-sitter-php": "0.23.11",
     "tree-sitter-python": "0.23.6",
     "tree-sitter-ruby": "0.23.1",
@@ -62,6 +60,9 @@
     "typescript": "^5.0.0",
     "vitest": "^2.1.9"
   },
+  "optionalDependencies": {
+    "sqlite-vss": "^0.1.2"
+  },
   "engines": {
     "node": ">=18.0.0"
   },