fix(ci): make @flapi/shared build standalone so the clients gate is green (#88)

* fix(ci): make @flapi/shared build standalone so the clients gate passes

The clients CI workflow built @flapi/shared in isolation and failed two ways,
both masked locally by dependency hoisting from cli/node_modules:

- shared/src imported axios-retry, boxen, camelcase, chalk, cli-table3,
  colorette, figures, lodash.kebabcase, log-symbols, ora and node builtins,
  but shared/package.json only declared axios + js-yaml. Declare the real deps
  (+ @types/node, @types/js-yaml).
- shared had no tsup.config, so tsup walked up to cli/tsup.config.ts and could
  not resolve tsup from the empty cli/ in CI. Add shared/tsup.config.ts.

Verified by building shared with cli/node_modules removed (true CI isolation).

* fix(ci): make the VSCode extension build standalone

The extension relied on axios being hoisted from cli/node_modules; in the
isolated CI job it failed to resolve 'axios' and cascaded into implicit-any /
strict errors.

- Source the AxiosInstance type from @flapi/shared (the single canonical axios)
  in the 8 type-only importers, avoiding a dual-axios type clash.
- Declare axios as a direct dependency for endpointTestService, which calls
  axios() at runtime, and coerce its broad header value types to string.

Verified by typechecking/building/testing the extension with cli/node_modules
removed (true CI isolation).

Author: jrosskopf

.github/workflows/clients.yaml

@@ -2,6 +2,10 @@ name: Clients (CLI + VSCode)
 
 # Compile/test gate for the TypeScript packages under cli/. This exists so a broken
 # build (like the extension being uncompilable for months) is caught on every PR.
+#
+# Each job builds @flapi/shared first: the CLI and the extension both resolve
+# @flapi/shared to its built dist/, and the extension's prebuild invokes shared's
+# tsup, which needs shared's devDependencies installed.
 
 on:
   push:
@@ -40,6 +44,11 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: '22'
+      - name: Build @flapi/shared (dependency)
+        working-directory: cli/shared
+        run: |
+          npm ci
+          npm run build
       - name: Build & test flapii CLI
         working-directory: cli
         run: |
@@ -54,6 +63,11 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: '22'
+      - name: Build @flapi/shared (dependency)
+        working-directory: cli/shared
+        run: |
+          npm ci
+          npm run build
       - name: Build, typecheck & test the VSCode extension
         working-directory: cli/vscode-extension
         run: |