[BUG] `strandly` workspace is never built or type-checked in CI

Filed as a follow-up from the review of #3734. Pre-existing gap; that PR is just what exposed it.

### Checks

- [x] I have updated to the lastest minor and patch version of Strands
- [x] I have checked the documentation and this is not expected behavior
- [x] I have searched [./issues](./issues?q=) and there are no duplicates of my issue

### SDK Language

TypeScript

### Strands Version

`main`

### Language Runtime Version

Node.js 22.14.0

### Operating System

Amazon Linux 2023 (aarch64)

### Installation Method

git clone

### Steps to Reproduce

1. Introduce a type error in the `strandly` workspace (or change its `typescript`/`@types/node` versions, as #3734 does).
2. Open a PR and watch CI.

### Expected Behavior

A change that breaks `strandly`'s build or types should fail CI.

### Actual Behavior

CI passes regardless. Nothing builds or type-checks `strandly`:

- Root `package.json:16-31` — the `build` / `lint` / `format:check` / `type-check` / `check` scripts are **all** `npm run <x> -w strands-ts`, never `-w strandly`.
- `strandly/package.json` defines its own `build` (`tsc`) and `type-check` (`tsc --noEmit`), but nothing invokes them.
- `grep -rn strandly .github/workflows/*.yml` — `strandly` appears only as a path-filter trigger (`ci.yml:40`, `typescript-pr-and-push.yml:9`, `typescript-integration-test.yml:8`), deciding *whether* the TypeScript workflow runs, never as a build or test target inside any job. `typescript-ts-check.yml` runs the root scripts, which resolve to `-w strands-ts` per above.

So a `strandly`-only change can trigger the TypeScript workflow and still never be compiled.

### Additional Context

Concrete illustration from #3734: it bumps `strandly`'s `typescript` `^6.0.3` → `^7.0.2` and `@types/node` `^25` → `^26`. I ran `cd strandly && npx tsc --noEmit` manually — 0 errors, so that PR is safe. But that's incidental: had the major bump broken `strandly`, CI would have been green anyway.

### Possible Solution

Either add `-w strandly` to the root `build`/`type-check`/`lint` scripts (or make them run across all workspaces), or add a small `strandly` job to the TypeScript workflow that invokes the scripts the workspace already defines. The second keeps failure attribution clearer.

### Related Issues

Found during review of #3734

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