feat: increase typescript strictness

[belgattitude]

Add by default

    "strict": true,
    "useUnknownInCatchVariables": true,
    "noImplicitOverride": true,
    "noUncheckedIndexedAccess": true,
    "allowUnreachableCode": false,
    "noFallthroughCasesInSwitch": true,
    "strictNullChecks": true,

[changeset-bot]

🦋 Changeset detected

Latest commit: e107ba8

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 4 packages

Name	Type
@httpx/dsn-parser	Patch
@httpx/exception	Patch
@httpx/json-api	Patch
@examples/nextjs-app	Patch

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[codecov]

Codecov Report

Merging #482 (9366bbe) into main (091cad0) will not change coverage.
The diff coverage is n/a.

❗ Current head 9366bbe differs from pull request most recent head e107ba8. Consider uploading reports for the commit e107ba8 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #482   +/-   ##
=======================================
  Coverage   93.38%   93.38%           
=======================================
  Files          60       60           
  Lines         408      408           
  Branches       59       59           
=======================================
  Hits          381      381           
  Misses         24       24           
  Partials        3        3           

Flag	Coverage Δ
httpx-exception-unit	93.38% <ø> (ø)

Impacted Files	Coverage Δ
packages/exception/src/base/HttpException.ts	100.00% <ø> (ø)