fix: typing decimals with a zero following the decimal point in app number fields

[allison-truhlar]

Addresses issue #459.

Number fields on the app launch form reject some decimal values as you type
them. Typing 0.01 into a field ends up as 1: when you reach 0.0, the form
parses it to 0 and redraws the field as 0, which drops the decimal point
before you type the last digit. Values with no zero right after the point,
such as 0.3 and 1.01, aren't affected.

This PR keeps the text you type in the field while it still equals the stored
number, so intermediate states like 0.0 stay on screen. When the stored value
changes some other way, for example when saved parameters are loaded, the
field shows the new value.

What changed

• frontend/src/components/ui/AppsPage/AppLaunchForm.tsx: ParameterField
  keeps the raw input text for number and integer fields and shows it
  while it parses to the stored value. The form still stores numbers, so
  validation, submission, and relaunch are unchanged.
• CLAUDE.md and docs/Development.md: the pixi run test-ui examples now
  use -- --. test-ui runs npm run test, and npm takes flags such as
  --ui, --trace, and -g as its own options, so with a single -- they
  never reached Playwright.
• docs/Development.md: adds instructions for running Playwright UI mode
  on a remote machine by serving it over HTTP and forwarding the port.

Tests

frontend/ui-tests/tests/apps-launch-form.spec.ts mocks an app manifest with
one number parameter, types 0.01 one key at a time, and checks that the
field still shows 0.01. The test fails without the fix: the field shows
1. It's a Playwright test because Vitest's jsdom environment doesn't
reproduce the browser's number-input behavior.

To test

1. Run pixi run test-ui -- -- tests/apps-launch-form.spec.ts and check that
   it passes.
2. In the running app, add an app that has a type: number parameter. The
   add-number-param branch of allison-truhlar/fileglancer-demo-app adds a
   --threshold parameter (default 0.05) for this.
3. Open the launch form, clear the field, and type 0.01. Check that the
   field shows 0.01.
4. Launch the job and check that its log shows Threshold: 0.01.

@krokicki

[krokicki]

Seems like something went wrong here?

[allison-truhlar]

Yes - not directly related to this PR, but I was trying to run the test in the Playwright UI mode and it wasn't working. It turned out npm run was swallowing the extra flags. Adding a double -- -- prior to the flags fixed it.

[krokicki]

And here, etc.