[web] Add compile-timeout-interstitial split test (#35286)

* [web] Add compile-timeout-interstitial split test

Show targeted interstitial copy to users arriving from the compile
timeout paywall (paywall-type=compile-timeout). Mirrors the existing
ai-limit-upgrade-copy pattern.

When enabled:
- H1 becomes "Upgrade for 24x more compile time"
- Standard/Pro card descriptions become compile-time targeted
- "24x Basic compile timeout" feature is bolded and hoisted to the top
  of the includes list (all plan types)

Part of #34982

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* Don't exclude trial users from the compile-timeout copy

* Add missing dot to translation

* Add "AI assistant" to student card

* Refactor how feature list is defined and ordered in pug file

* Replace `aiLimitUpgradeCopy` and `compileTimeoutInterstitial` boolean by `upgradeCopy` string

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
GitOrigin-RevId: 6c7c7e0457f93284d6798be229da5513f92ca77c

services/web/locales/en.json

@@ -444,6 +444,7 @@
   "compile_error_entry_description": "An error which prevented this project from compiling",
   "compile_error_handling": "Compile error handling",
   "compile_larger_projects": "Compile larger projects",
+  "compile_longer_more_complex_docs_with_24x": "Compile longer, more complex docs with 24x the compile time of the free plan.",
   "compile_mode": "Compile mode",
   "compile_servers": "Compile servers",
   "compile_servers_info_new": "The servers used to compile your project. Compiles for users on paid plans always run on the fastest available servers.",
@@ -1622,6 +1623,7 @@
   "more_collabs_per_project": "More collaborators per project",
   "more_comments": "More comments",
   "more_compile_time": "More compile time",
+  "more_compile_time_along_with_highest_ai_allowance": "More compile time along with our highest AI allowance.",
   "more_editor_toolbar_item": "More editor toolbar items",
   "more_info": "More Info",
   "more_options": "More options",
@@ -2930,6 +2932,7 @@
   "updating_site": "Updating Site",
   "upgrade": "Upgrade",
   "upgrade_cc_btn": "Upgrade now, pay after 7 days",
+  "upgrade_for_24x_more_compile_time": "Upgrade for 24x more compile time",
   "upgrade_for_more_compile_time": "Upgrade to get more compile time",
   "upgrade_for_our_highest_ai_allowance": "Upgrade for our highest AI allowance",
   "upgrade_for_unlimited_access_to_ai": "Upgrade to keep using AI features, or wait __time__ for your limit to reset.",