feat(operator-demo-video): add login and workflow-navigation controllers

[xuang7]

What changes were proposed in this PR?

This PR adds the first two UI controllers of the demo video generator: signing in and getting a workflow onto the canvas.

Changes:

• LoginControllerBuilder: navigates to /login and signs in with the local account; skips the form when the session is already authenticated, and fails with a screenshot when the login page never appears.
• NavigationControllerBuilder: createNewWorkflow (used by source-operator demos, which start from an empty canvas) and importWorkflow, which uploads a workflow JSON from the workflow listing and opens the resulting entry. Covering both the list and card views of the listing.
• The timing constants (Delays/Timeouts) the two controllers wait on; later controllers extend these.
• Six data-testid hooks the controllers locate elements by (login form ×3, create/upload buttons, workflow canvas), each covered by a guard test in the component's existing spec so renaming or removing one fails CI instead of silently breaking recording.

Any related issues, documentation, discussions?

Closes #7520
Depends on #7594.

How was this PR tested?

sbt DemoVideoGenerator/compile, scalafmtCheck, and scalafix --check all pass; the three touched component specs (157 tests, including the new guard tests) pass. The upload-import flow was verified end-to-end against a local
deployment by recording an operator demo video with it.

Was this PR authored or co-authored using generative AI tooling?

Generated-by: Claude Code (Claude Fable 5)

[github-actions]

Automated Reviewer Suggestions

Based on the git blame history of the changed files, we recommend the following reviewers:

• Contributors with relevant context: @Neilk1021, @kunwp1, @Ma77Ball
  You can notify them by mentioning @Neilk1021, @kunwp1, @Ma77Ball in a comment.

[xuang7]

Could you take a look when you're available? Thanks! @carloea2

[github-actions]

⚠️ Benchmark changes need a look

🟢 2 better · 🔴 5 worse · ⚪ 8 noise (<±5%) · 0 without baseline

Compared against main 71faf44 benchmarked on this same runner, so the delta is largely free of cross-runner hardware noise. The "7d avg" column still reflects the gh-pages dashboard. Treat <±5% as noise unless repeated.

Dashboard · Run

	config	throughput	MB/s	latency	max Δ latest / 7d
🔴	bs=10 sw=10 sl=64	388	0.237	25,897/33,087/33,087 us	🔴 +13.8% / 🔴 +103.2%
🔴	bs=100 sw=10 sl=64	905	0.552	105,044/164,408/164,408 us	🔴 +14.6% / 🔴 +51.9%
⚪	bs=1000 sw=10 sl=64	1,097	0.67	911,511/1,024,078/1,024,078 us	⚪ within ±5% / 🟢 -8.5%

Baseline details

Latest main 71faf44 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	388 tuples/sec	429 tuples/sec	775.33 tuples/sec	-9.6%	-50.0%
bs=10 sw=10 sl=64	MB/s	0.237 MB/s	0.262 MB/s	0.473 MB/s	-9.5%	-49.9%
bs=10 sw=10 sl=64	p50	25,897 us	22,758 us	12,743 us	+13.8%	+103.2%
bs=10 sw=10 sl=64	p95	33,087 us	34,934 us	16,310 us	-5.3%	+102.9%
bs=10 sw=10 sl=64	p99	33,087 us	34,934 us	18,926 us	-5.3%	+74.8%
bs=100 sw=10 sl=64	throughput	905 tuples/sec	909 tuples/sec	1,001 tuples/sec	-0.4%	-9.6%
bs=100 sw=10 sl=64	MB/s	0.552 MB/s	0.555 MB/s	0.611 MB/s	-0.5%	-9.6%
bs=100 sw=10 sl=64	p50	105,044 us	106,202 us	101,399 us	-1.1%	+3.6%
bs=100 sw=10 sl=64	p95	164,408 us	143,446 us	108,206 us	+14.6%	+51.9%
bs=100 sw=10 sl=64	p99	164,408 us	143,446 us	118,195 us	+14.6%	+39.1%
bs=1000 sw=10 sl=64	throughput	1,097 tuples/sec	1,108 tuples/sec	1,026 tuples/sec	-1.0%	+6.9%
bs=1000 sw=10 sl=64	MB/s	0.67 MB/s	0.676 MB/s	0.626 MB/s	-0.9%	+7.0%
bs=1000 sw=10 sl=64	p50	911,511 us	905,411 us	996,304 us	+0.7%	-8.5%
bs=1000 sw=10 sl=64	p95	1,024,078 us	975,461 us	1,042,531 us	+5.0%	-1.8%
bs=1000 sw=10 sl=64	p99	1,024,078 us	975,461 us	1,074,934 us	+5.0%	-4.7%

Raw CSV

config_idx,batch_size,schema_width,string_len,num_batches,total_ms,total_tuples,total_bytes,tuples_per_sec,mb_per_sec,lat_p50_us,lat_p95_us,lat_p99_us
0,10,10,64,20,514.94,200,128000,388,0.237,25897.33,33086.87,33086.87
1,100,10,64,20,2210.04,2000,1280000,905,0.552,105043.53,164407.53,164407.53
2,1000,10,64,20,18230.46,20000,12800000,1097,0.670,911511.15,1024077.69,1024077.69