chore(workspace): tsconfig composite refs + axe-linter false-positive config

Three editor-noise sources, three matching tame:

* Add `composite: true` to lib tsconfig.lib.json files (shared/ui,
  shared/state, feature/auth) and let `nx sync` redirect consumer
  references in apps/portal-{shell,admin}/tsconfig.app.json to point
  at the .lib.json directly. Silences TS6306 ("Referenced project
  must have setting composite: true") that the TS service raises on
  the project references our Nx 22 lib generator emits.

* Add `ignoreDeprecations: "5.0"` on apps/portal-bff/tsconfig.{app,
  spec}.json. Both inherit `moduleResolution: node` / `node10` which
  TS 7.0 will remove; the diagnostic itself suggests the opt-out
  knob. The TS 5.9 we run only accepts "5.0" as the value (the
  warning text mentions "6.0" but TS rejects it). Migration to
  nodenext/node16 is a separate chantier — too entangled with Nest
  CJS semantics for a drive-by.

* Add a repo-level .axe-linter.yml that disables the `list` rule
  globally. axe Linter (VS Code) doesn't understand Angular 17+
  `@for` blocks and flags `@for (...) { <li>… }` as a non-<li>
  child of <ul>/<ol>. Compiler erases the syntax at build time;
  axe-playwright (ADR-0016) operates on the rendered DOM and is
  unaffected.

libs/shared/ui/tsconfig.lib.json

@@ -1,6 +1,7 @@
 {
   "extends": "./tsconfig.json",
   "compilerOptions": {
+    "composite": true,
     "outDir": "../../../dist/out-tsc",
     "declaration": true,
     "declarationMap": true,