Finish axios migration via shared native HTTP helper

Replace all in-scope axios callsites with a new helpers/http.js wrapper over native fetch, including JSON/text GET, JSON POST, HEAD checks, and transient 5xx retry behavior; update all browser, build, script, and proxy API clients to use it; add focused unit tests; and remove axios from package dependencies.

Constraint: Preserve API/build and deployment behavior while lowering transport surface area.

Rejected: inline fetch replacements at each callsite | rejected to avoid inconsistent error/retry semantics.

Confidence: high

Scope-risk: moderate

Directive: Keep helper in place as the transport boundary and update tests when changing request semantics.

Tested: pnpm run -s typecheck, pnpm -s run test-prebuild, pnpm -s run test, pnpm -s run test:browser, pnpm -s run netlify-build, smoke GETs on /apple-silicon-app-test and /apple-silicon-app-test/?version=2

Not-tested: branch/netlify deployment health in CI pipeline after merge

helpers/api/client.js

@@ -12,9 +12,8 @@
 // GET /api/tiles/public/static/3/4/2.json?turn=37038&games=wot
 // DoesItAPI.tiles.public.static(3)(4)(`${2}.json`).get({ turn: 37, games: 'wot' })
 
-import axios from 'axios'
-
 import { getApiUrl } from '~/helpers/url.js'
+import { requestJson } from '~/helpers/http.js'
 
 // Use msw
 import '~/test/msw/use.js'
@@ -22,8 +21,7 @@ import '~/test/msw/use.js'
 // const defaultFetchMethod = (...args) => console.log(...args) // mock
 
 const defaultFetchMethod = async function (...args) {
-    return axios(...args)
-        .then( response => response.data )
+    return requestJson(...args)
         .catch( error => {
             if ( error?.response?.status !== 404 ) {
                 console.error( error )