fix(ci): use cache for eslint/prettier/typecheck to speed up dev cycle

[Hweinstock]

Description

Adds --cache to eslint and prettier, and --incremental to tsc across npm scripts and the lint-staged pre-commit hook.

Benchmarks

Tool	Cold	Warm (cached)	Speedup
ESLint	38.5s	4.0s	~9.5x
Prettier	9.9s	2.8s	~3.5x
TypeScript	12.4s	7.2s	~1.7x

References

• ESLint --cache
• Prettier --cache
• TypeScript --incremental

Related Issue

Closes #

Documentation PR

N/A

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe): Developer experience / performance improvement

Testing

How have you tested the change?

• I ran npm run test:unit and npm run test:integ
• I ran npm run typecheck
• I ran npm run lint
• If I modified src/assets/, I ran npm run test:update-snapshots and committed the updated snapshots

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

---

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terms of your choice.

[agentcore-devx-automation]

Claude Security Review: no high-confidence findings. (run)

[github-actions]

Package Tarball

aws-agentcore-0.15.0.tgz

How to install

gh release download pr-1390-tarball --repo aws/agentcore-cli --pattern "*.tgz" --dir /tmp/pr-tarball
npm install -g /tmp/pr-tarball/aws-agentcore-0.15.0.tgz

[agentcore-cli-automation]

LGTM. Small, focused change that's safe to merge:

• All three tools support the flags at the pinned versions (ESLint 9, Prettier 3, TS 5).
• .eslintcache, .cache, and *.tsbuildinfo are already in .gitignore, so no risk of accidentally committing cache artifacts.
• Prettier writes its cache under node_modules/.cache/prettier/ by default; ESLint and TS write to repo root — none of these intersect with what CI persists between runs (CI only restores node_modules keyed on npm-shrinkwrap.json, so stale caches from prior CI runs aren't a concern).
• lint-staged passing specific file paths with --cache works correctly — the cache is keyed per file.

Nice speedup for local dev iteration.