Make every button say what it does, and only show the ones that help

[rndaom]

Several buttons were hard to understand. Some used words like "build" and "draft", some repeated a control already on the page, Removing the crosshair pack was hidden behind ⋯, and Comfig showed four buttons, including an orange Update packages even when packages were up to date. This applies one set of rules to every pane.

What changes

• Changes waiting for TF2. Crosshair, Viewmodels and Mods → Casual setup share one sticky bar while changes aren't in TF2 yet. It shows the orange change dot, one line saying what's waiting, Discard changes and Apply changes (Close TF2 to apply while TF2 runs).
  • Viewmodels applies straight from the bar; the review window is gone. Applying an all-shown draft over a built pack removes the pack.
  • Casual setup's side panel becomes a summary with Restore stock files….
• Crosshair. The pack moves out of the header's ⋯ menu into a Crosshair pack section with Remove pack…. The rebuild notices now say Repair pack or Update pack.
• Comfig. Packages is one row whose update button appears only when a newer release exists or packages are missing (Update to 9.100.2). The comfig.app customizer sits next to the comfig-custom folder it makes (Open comfig.app, Add folder…).
• Viewmodels.
  • Every class… is now Set every class….
  • A Viewmodel pack section has Use your own VPK….
  • Open Comfig addons is removed; the switch above it already does the job.
  • The unlabeled reread button is removed. The catalog is read again when the pane opens or execs regains focus after the last read is two minutes old.
• Launch. When this profile's options and Steam's differ, both are shown side by side, with Use this profile's options and Use Steam's options. The safety flow is unchanged: Steam must be closed to write, and every choice is explicit.
• Elsewhere.
  • Gameplay drops its Open Viewmodels section.
  • Sounds puts Remove sound files beside the sounds it removes.
  • Copy to profiles… is now Copy to other profiles….
  • Opening another site is a text link, not a button.

The button rules are in the design system in docs/ARCHITECTURE.md. The pane guides and the changelog are updated.

Like #169, this touches ViewmodelBuilder.tsx, which #168 also changes. Whichever lands second keeps #168's out-of-date notice and "stays partly visible" lines.

Checks

• pnpm test: all 1,419 desktop tests pass.
• pnpm check and tsc pass.
• Checked in the browser preview at 1280×800 and 960×640: Comfig, Crosshair, Viewmodels, Mods, Launch and Sounds.