feat: add 22 new skills + reorganize into categorized structure

Adds 22 new security-approved skills and reorganizes all 35 skills
into categorized directory structure per the Skills Organization doc.

Structure:
  skills/
    foundations/ (6 skills)
    services-and-workloads/
      serverless/ (6 skills)
      vpc/ (3 skills)
      databases/ (2 skills)
      ec2/ (3 skills)
      storage/ (8 skills)
      observability/ (3 skills)
      bedrock/
      containers/
      billing-and-cost-management/
      aws-cleanrooms/
      aws-transform/

Skipped: 5 analytics skills pending security approval.
Removed: mounting-efs-on-ec2 (replaced by setup-efs).
Note: ~30 markdown lint errors remain from source files.

Author: krishmakochhar

.markdownlint-cli2.yaml

@@ -7,6 +7,10 @@ config:
     allowed_elements:
       - details
       - summary
+      - Resource
+      - model-id
+      - region
+      - Name
   MD024:
     siblings_only: true
   MD026: false

skills/foundations/aws-sdk-js-v3-usage/SKILL.md

@@ -0,0 +1,254 @@
+---
+name: aws-sdk-js-v3-usage
+description: |
+  AWS SDK for JavaScript v3 development patterns. Use when writing JavaScript or TypeScript code that uses AWS services via @aws-sdk/* packages (aws-sdk-js-v3), or when asked about schemas, runtime validation, serialization, or code generation in the context of the JS/TS AWS SDK.
+---
+
+> Do not use emojis in any code, comments, or output when this skill is active.
+
+# AWS SDK for JavaScript v3
+
+## Package Structure
+
+- `@aws-sdk/client-*` — one per service, generated by [smithy-typescript](https://github.com/awslabs/smithy-typescript); one-to-one with AWS services and operations
+- `@aws-sdk/lib-*` — higher-level helpers (e.g. `lib-dynamodb`, `lib-storage`)
+- `@aws-sdk/*` (no prefix) — utility packages (mostly internal; don't import deep paths)
+
+Always import from the package root:
+
+```js
+import { S3Client } from "@aws-sdk/client-s3"; // correct
+// NOT: import { S3Client } from "@aws-sdk/client-s3/dist-cjs/S3Client"
+```
+
+## Two Client Styles
+
+**Bare-bones** (preferred — smaller bundle):
+
+```js
+import { S3Client, GetObjectCommand } from "@aws-sdk/client-s3";
+const client = new S3Client({ region: "us-east-1" });
+const output = await client.send(new GetObjectCommand({ Bucket: "b", Key: "k" }));
+```
+
+**Aggregated** (v2-style but NOT v2, larger bundle):
+
+```js
+import { S3 } from "@aws-sdk/client-s3";
+const client = new S3({ region: "us-east-1" });
+const output = await client.getObject({ Bucket: "b", Key: "k" });
+```
+
+## Client Configuration
+
+No global config in v3 — pass config to each client. `region` is always required; set it explicitly or via `AWS_REGION` env var.
+
+```js
+const config = { region: "us-east-1", maxAttempts: 5 };
+const s3 = new S3Client(config);
+const dynamo = new DynamoDBClient(config);
+```
+
+**Do not read or mutate `client.config` after instantiation** — it is a resolved form (e.g. `region` becomes an async function). See `references/effective-practices.md`.
+
+For HTTP handler (`NodeHttpHandler` from `@smithy/node-http-handler`), retry strategy, endpoint details, logging, FIPS, dual-stack, protocol selection, and S3-specific options → see `references/clients.md`.
+
+## Credentials
+
+All providers from `@aws-sdk/credential-providers`. Credentials are lazy and cached per client until ~5 min before expiry.
+
+```js
+// Default chain (env → ini → IMDS/ECS) — use in most Node.js apps
+const client = new S3Client({ credentials: fromNodeProviderChain() });
+
+// Assume role (NOTE: fromTemporaryCredentials is correct for STS AssumeRole)
+const client = new S3Client({
+  credentials: fromTemporaryCredentials({ params: { RoleArn: "arn:aws:iam::123456789012:role/MyRole" } }),
+});
+
+// Named profile
+const client = new S3Client({ profile: "my-profile" });
+```
+
+Share credentials and socket pool across multi-region clients:
+
+```js
+const east = new S3Client({ region: "us-east-1" });
+const { credentials, requestHandler } = east.config;
+const west = new S3Client({ region: "us-west-2", credentials, requestHandler });
+```
+
+For all providers (Cognito, SSO, web identity, custom chains, STS region priority) → see `references/credentials.md`.
+
+## Streams (e.g. S3 GetObject Body)
+
+**Always read or discard streaming responses** — unread streams leave sockets open (socket exhaustion):
+
+```js
+const { Body } = await client.send(new GetObjectCommand({ Bucket: "b", Key: "k" }));
+const str = await Body.transformToString();       // read as string
+const bytes = await Body.transformToByteArray();  // read as Uint8Array
+// or discard:
+await (Body.destroy?.() ?? Body.cancel?.());
+```
+
+Streams can only be read once.
+
+## Paginators
+
+Use `paginate*` functions instead of manual token handling:
+
+```js
+import { DynamoDBClient, paginateListTables } from "@aws-sdk/client-dynamodb";
+
+const client = new DynamoDBClient({});
+
+const tableNames = [];
+for await (const page of paginateListTables({ client }, {})) {
+  // page contains a single paginated output.
+  tableNames.push(...page.TableNames);
+}
+```
+
+## DynamoDB DocumentClient
+
+Use `@aws-sdk/lib-dynamodb` to work with native JS types instead of AttributeValues:
+
+```js
+import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
+import { DynamoDBDocumentClient, GetCommand, PutCommand } from "@aws-sdk/lib-dynamodb";
+
+const client = DynamoDBDocumentClient.from(new DynamoDBClient({}));
+await client.send(new PutCommand({ TableName: "T", Item: { id: "1", name: "Alice" } }));
+const { Item } = await client.send(new GetCommand({ TableName: "T", Key: { id: "1" } }));
+```
+
+For marshall options, large numbers (NumberValue), pagination, and aggregated client → see `references/dynamodb.md`.
+
+## S3: Presigned URLs, Multipart Upload, Waiters
+
+```js
+// Presigned GET URL
+import { getSignedUrl } from "@aws-sdk/s3-request-presigner";
+const url = await getSignedUrl(client, new GetObjectCommand({ Bucket: "b", Key: "k" }), { expiresIn: 3600 });
+
+// Multipart upload (large files / streams)
+import { Upload } from "@aws-sdk/lib-storage";
+const upload = new Upload({ client, params: { Bucket: "b", Key: "k", Body: stream } });
+await upload.done();
+
+// Waiters
+import { waitUntilObjectExists } from "@aws-sdk/client-s3";
+await waitUntilObjectExists({ client, maxWaitTime: 120 }, { Bucket: "b", Key: "k" });
+```
+
+For presigned POST, signed headers, waiter options → see `references/s3.md`.
+
+## Error Handling
+
+```js
+import { S3ServiceException } from "@aws-sdk/client-s3";
+
+try {
+  await client.send(new GetObjectCommand({ Bucket: "b", Key: "k" }));
+} catch (e) {
+  if (e?.$metadata) {
+    // SDK service error — has $metadata.httpStatusCode, e.name, e.$response
+    console.error(e.name, e.$metadata.httpStatusCode);
+  }
+}
+```
+
+Check `e.name` or `instanceof` for specific error types. See `references/error-handling.md` for full patterns.
+
+For **runtime validation, serialization to non-default formats, or questions about what schemas are** in jsv3 → see `references/schemas.md`.
+
+## Performance: Parallel Workloads
+
+```js
+// Configure maxSockets to match your parallel batch size
+const client = new S3Client({
+  requestHandler: { httpsAgent: { maxSockets: 50 } },
+  cacheMiddleware: true, // skip if using custom middleware
+});
+```
+
+**Streaming deadlock warning**: with limited sockets, don't `await` the request and stream body separately — chain them. See `references/performance.md`.
+
+## Middleware
+
+Add custom logic to all commands on a client:
+
+```js
+client.middlewareStack.add(
+  (next, context) => async (args) => {
+    console.log(context.commandName, args.input);
+    const result = await next(args);
+    return result;
+  },
+  { name: "MyMiddleware", step: "build", override: true }
+);
+```
+
+Steps (in order): `initialize` → `serialize` → `build` → `finalizeRequest` → `deserialize`
+
+## Abort Controller
+
+```js
+const { AbortController } = require("@aws-sdk/abort-controller");
+const { S3Client, CreateBucketCommand } = require("@aws-sdk/client-s3");
+
+const abortController = new AbortController();
+const client = new S3Client(clientParams);
+
+const requestPromise = client.send(new CreateBucketCommand(commandParams), {
+  abortSignal: abortController.signal,
+});
+
+// The request will not be created if abortSignal is already aborted.
+// The request will be destroyed if abortSignal is aborted before response is returned.
+abortController.abort();
+
+// This will fail with "AbortError" as abortSignal is aborted.
+await requestPromise;
+```
+
+## Lambda Best Practices
+
+Initialize clients **outside** the handler (container reuse), make API calls **inside**. For one-time async setup, use a lazy init flag inside the handler:
+
+```js
+import { S3Client } from "@aws-sdk/client-s3";
+
+const client = new S3Client({}); // outside — reused across invocations
+
+let ready = false;
+export const handler = async (event) => {
+  if (!ready) { await prepare(); ready = true; } // lazy one-time setup inside handler
+  // ... API calls here
+};
+```
+
+See `references/lambda.md` for Lambda layers and versioning.
+
+## Node.js Version Requirements
+
+- v3.968.0+ requires Node.js >= 20
+- v3.723.0+ requires Node.js >= 18
+
+## TypeScript
+
+Response fields are typed as `T | undefined` by default. Use `AssertiveClient` from `@smithy/types` to remove `| undefined`, or `NodeJsClient` / `BrowserClient` to narrow streaming blob types. See `references/typescript.md`.
+
+## SigV4a (S3 Multi-Region Access Points)
+
+S3 MRAP and certain other features require SigV4a. You must install and side-effect-import exactly one of:
+
+- `@aws-sdk/signature-v4-crt` — Node.js only, better performance
+- `@aws-sdk/signature-v4a` — Node.js + browsers, pure JS
+
+```js
+import "@aws-sdk/signature-v4a"; // side-effect only — no exported values needed
+```
+
+See `references/sigv4a.md` for full details and MRAP ARN format.