TB Angular upgrade 19

[cdavalos7]

Motivation for features / changes

Migrate Angular from 18 to 19 following the Angular update guide. As a side change, Node.js is also upgraded from 18 to 22.23.1 LTS to prepare for the next major version step.

Technical description of changes

• All @angular/* packages (core, material, cdk, router, forms, build, cli, etc.) bumped to ^19.0.0
• NgRx (@ngrx/store, @ngrx/effects) bumped to ^19.0.0
• TypeScript updated to 5.6.3 to satisfy Angular 19's peer requirement (>=5.5 <5.9)
• zone.js updated to ~0.15.0 (Angular 19 core requires this range)
• Build-tooling patch for Bazel updated to the matching v19 commit (fdca582c). Same esbuild tree-shaking fix carried forward
• Node.js bumped from 18.20.8 to 22.23.1 LTS in WORKSPACE and ci.yml

Angular 19 changes the default value of the standalone flag to true, which means any component, directive, or pipe that omits it is now treated as standalone. This repo is fully NgModule-based, so all 206 declarations already had standalone: false set explicitly from a prior migration step. No changes were needed and the build compiled clean.

Detailed steps to verify changes work correctly (as executed by you)

• Bundle consistent size verified post-upgrade: 2.70 MB, all three markers present (bootstrapModule, tb-webapp, zone.js).
• bazel build //tensorboard/webapp:tb_webapp_binary.js
• bazel run //tensorboard