refactor(database/NVD)!: implement all parameters and minimal timeout

docs/database/nvd.md

@@ -1,21 +1,31 @@
 # NVD
 
-NVD stand for <kbd>National Vulnerability Database</kbd>, which is the U.S. government repository of standards-based vulnerability management data. This database is maintained by NIST (National Institute of Standards and Technology).
+NVD stands for <kbd>National Vulnerability Database</kbd>, which is the U.S. government repository of standards-based vulnerability management data. This database is maintained by NIST (National Institute of Standards and Technology).
 
 ## Implementation Notes
 
 The NVD integration uses the REST API (v2.0) available at [services.nvd.nist.gov](https://services.nvd.nist.gov/rest/json/cves/2.0).
 
 ### Search Parameters
 
-While the NVD API supports CPE matching via the `cpeMatchString` parameter, we've chosen to use only keyword search for NPM packages. This decision was made because:
+While the NVD API supports CPE matching via parameters like `cpeName` and `virtualMatchString`, we've chosen not to use them for NPM packages. This decision was made because:
 
 1. The CPE format for npm packages is not standardized in NVD
 2. Attempted CPE patterns (like `cpe:2.3:a:*:package-name:*:*:*:*:*:node.js:*:*`) resulted in 404 errors
 3. Keyword search provides more flexible results for JavaScript/NPM packages
 
 The implementation might be enhanced in the future if NVD provides clearer guidelines for CPE matching of npm packages.
 
+### Parameter Constraints
+
+Some parameters have mutual exclusivity constraints enforced by the NVD API:
+
+- `cvssV2Severity`, `cvssV3Severity`, and `cvssV4Severity` cannot be combined with each other.
+- `cvssV2Metrics`, `cvssV3Metrics`, and `cvssV4Metrics` cannot be combined with each other.
+- `keywordExactMatch` requires `keywordSearch` to be set.
+- `pubStartDate` and `pubEndDate` must be used together; the maximum range is 120 days.
+- `lastModStartDate` and `lastModEndDate` must be used together; the maximum range is 120 days.
+
 ## Format
 
 The NVD API returns detailed vulnerability information.
@@ -46,35 +56,109 @@ const db = new vulnera.Database.NVD({
 
 ```ts
 export interface NVDOptions {
-  credential?: ApiCredential;
+  credential: ApiCredential;
+  /**
+   * Delay in milliseconds between consecutive requests in findMany.
+   *
+   * The NVD API enforces rate limits:
+   * - Without API key: 5 requests per 30-second window → set ~6 000 ms
+   * - With API key:   50 requests per 30-second window → set ~600 ms
+   *
+   * @default 6000
+   */
+  requestDelay?: number;
 }
 ```
 
-### `findOne(parameters: NVDApiParameter): Promise<NVD[]>`
-Find the vulnerabilities of a given package using available NVD API parameters.
+> **Rate limiting:** The NVD API enforces strict rate limits (see [NVD developer docs](https://nvd.nist.gov/developers/start-here)). `findMany` sends requests sequentially with a `requestDelay` pause between each one to avoid being throttled. The default of 6 000 ms is safe for unauthenticated use. If you supply an API key you can safely lower it to ~600 ms.
+
+### `find(parameters: NVDApiParameter): Promise<NVD[]>`
+Find vulnerabilities using any combination of available NVD API parameters.
 
 ```ts
 export type NVDApiParameter = {
+  // Keyword search
   keywordSearch?: string;
+  keywordExactMatch?: boolean;
+
+  // Convenience fields (used by findBySpec / findMany)
+  packageName?: string;
+  ecosystem?: string; // default: "npm"
+
+  // CVE identification
+  cveId?: string;
+  cveTag?: "disputed" | "unsupported-when-assigned" | "exclusively-hosted-service";
   cweId?: string;
+  sourceIdentifier?: string;
+
+  // CVSS severity (mutually exclusive across versions)
+  cvssV2Severity?: "LOW" | "MEDIUM" | "HIGH";
   cvssV3Severity?: "CRITICAL" | "HIGH" | "MEDIUM" | "LOW";
-  packageName?: string;
-  ecosystem?: string;
+  cvssV4Severity?: "CRITICAL" | "HIGH" | "MEDIUM" | "LOW";
+
+  // CVSS vector strings (mutually exclusive across versions)
+  cvssV2Metrics?: string;
+  cvssV3Metrics?: string;
+  cvssV4Metrics?: string;
+
+  // Boolean flags
+  noRejected?: boolean;
+  hasKev?: boolean;
+  hasCertAlerts?: boolean;
+  hasCertNotes?: boolean;
+  hasOval?: boolean;
+
+  // Date ranges (ISO-8601, max 120-day window per pair)
+  pubStartDate?: string;
+  pubEndDate?: string;
+  lastModStartDate?: string;
+  lastModEndDate?: string;
+
+  // Pagination
+  resultsPerPage?: number; // default and max: 2000
+  startIndex?: number;     // default: 0
 };
 ```
 
-### `findOneBySpec(spec: string): Promise<NVD[]>`
-Find the vulnerabilities of a given package using the NPM spec format like `packageName@version`.
+**Examples:**
+
+```ts
+// Filter by CVSSv3 severity
+const vulns = await db.find({ keywordSearch: "express", cvssV3Severity: "CRITICAL" });
+
+// Return only CVEs in the CISA Known Exploited Vulnerabilities catalog
+const kevVulns = await db.find({ keywordSearch: "log4j", hasKev: true });
+
+// Paginate results
+const page2 = await db.find({ keywordSearch: "lodash", resultsPerPage: 100, startIndex: 100 });
+
+// Filter by publication date range
+const recent = await db.find({
+  pubStartDate: "2024-01-01T00:00:00.000Z",
+  pubEndDate:   "2024-04-30T23:59:59.000Z"
+});
+```
+
+### `findByCveId(cveId: string): Promise<NVD[]>`
+Find a specific vulnerability by its CVE identifier.
+
+```ts
+const vuln = await db.findByCveId("CVE-2021-44228");
+console.log(vuln);
+```
+
+### `findBySpec(spec: string): Promise<NVD[]>`
+Find vulnerabilities of a given package using the NPM spec format `packageName@version`.
 
 ```ts
-const vulns = await db.findOneBySpec("express@4.0.0");
+const vulns = await db.findBySpec("express@4.0.0");
 console.log(vulns);
 ```
 
 ### `findMany<T extends string>(specs: T[]): Promise<Record<T, NVD[]>>`
-Find the vulnerabilities of many packages using the spec format.
+Find vulnerabilities for many packages using the spec format.
 
-Returns a Record where keys are equals to the provided specs.
+Returns a Record where keys are equal to the provided specs.
 
 ```ts
 const vulns = await db.findMany(["express@4.0.0", "lodash@4.17.0"]);