feat(TRUEREF-0013): implement trueref.json config file support

- Lenient parser for trueref.json and context7.json (trueref.json takes precedence)
- Validates folders, excludeFolders, excludeFiles, rules, previousVersions
- Stores config in repository_configs table
- JSON Schema served at GET /api/v1/schema/trueref-config.json for IDE validation
- Rules injected at top of every query-docs response

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

src/lib/server/config/trueref-config.json

@@ -0,0 +1,85 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://trueref.dev/schema/trueref-config.json",
+  "title": "TrueRef Repository Configuration",
+  "description": "Configuration file for controlling how a repository is indexed and presented by TrueRef. Place as trueref.json (or context7.json for backward compatibility) at the root of your repository.",
+  "type": "object",
+  "additionalProperties": false,
+  "properties": {
+    "projectTitle": {
+      "type": "string",
+      "minLength": 1,
+      "maxLength": 100,
+      "description": "Override the display name for this library. When set, this replaces the repository name in search results and UI."
+    },
+    "description": {
+      "type": "string",
+      "minLength": 10,
+      "maxLength": 500,
+      "description": "A short description of the library used for search ranking and display. Should accurately describe the library's purpose."
+    },
+    "folders": {
+      "type": "array",
+      "maxItems": 50,
+      "description": "Allowlist of folder path prefixes or regex strings to include in indexing. If empty or absent, all folders are included. Examples: [\"src/\", \"docs/\", \"^packages/core\"]",
+      "items": {
+        "type": "string",
+        "maxLength": 200,
+        "description": "A path prefix or regex string. Paths are matched against the full relative file path within the repository."
+      }
+    },
+    "excludeFolders": {
+      "type": "array",
+      "maxItems": 50,
+      "description": "Folders to exclude from indexing. Applied after the 'folders' allowlist. Examples: [\"test/\", \"fixtures/\", \"__mocks__\"]",
+      "items": {
+        "type": "string",
+        "maxLength": 200,
+        "description": "A path prefix or regex string for folders to exclude."
+      }
+    },
+    "excludeFiles": {
+      "type": "array",
+      "maxItems": 100,
+      "description": "Exact filenames to exclude (no path, no regex). Examples: [\"README.md\", \"CHANGELOG.md\", \"jest.config.ts\"]",
+      "items": {
+        "type": "string",
+        "maxLength": 200,
+        "description": "An exact filename (not a path). Must not contain path separators."
+      }
+    },
+    "rules": {
+      "type": "array",
+      "maxItems": 20,
+      "description": "Best practices and rules to inject at the top of every query-docs response. These are shown to AI coding assistants to guide correct library usage.",
+      "items": {
+        "type": "string",
+        "minLength": 5,
+        "maxLength": 500,
+        "description": "A single best-practice rule or guideline for using this library."
+      }
+    },
+    "previousVersions": {
+      "type": "array",
+      "maxItems": 50,
+      "description": "Previously released versions to make available for versioned documentation queries.",
+      "items": {
+        "type": "object",
+        "required": ["tag", "title"],
+        "additionalProperties": false,
+        "properties": {
+          "tag": {
+            "type": "string",
+            "pattern": "^v?\\d+\\.\\d+(\\.\\d+)?(-.*)?$",
+            "description": "Git tag name for this version (e.g. \"v1.2.3\", \"2.0.0-beta.1\")."
+          },
+          "title": {
+            "type": "string",
+            "minLength": 1,
+            "description": "Human-readable version label (e.g. \"Version 1.2.3\", \"v2 Legacy\")."
+          }
+        }
+      }
+    }
+  }
+}