Use PLATFORM_NAME instead of hard-coding the app name

AGENTS.md

@@ -126,6 +126,7 @@ callbacks and hot paths.
 **CRITICAL Code Style Guidelines:**
 
 - **No `null`** - only use `undefined`
+- Never hard-code the app's name. The brand is a build-time `VITE_PLATFORM_*` variable, so user-facing copy interpolates `PLATFORM_NAME` from `@app/env`, and `PLATFORM_URL`, `PLATFORM_LOGO`, `PLATFORM_ABOUT` for the rest of it. Each is set by the deployment, so don't write a `"Flotilla"` fallback behind one either.
 - Svelte 5 runes (`$state`, `$derived`, `$effect`) only in UI components
 - TailwindCSS styling with css components customized by theme. See lib/components for examples.
 - Comments, naming, conditionals and single-use indirection are covered by the Cleanup Pass above.

src/app/components/HomeHosting.svelte

@@ -12,6 +12,7 @@
   import {user} from "@app/core"
   import {pushModal} from "@app/modal"
   import {HostingError, listTenantRelays, type HostedRelay} from "@app/hosting"
+  import {PLATFORM_NAME} from "@app/env"
 
   const {class: className = ""}: {class?: string} = $props()
 
@@ -58,8 +59,8 @@
         {#if relays.length > 0}
           Spin up another hosted space — rooms, calendar and moderation included.
         {:else}
-          Don't wait for an invite. Flotilla Hosting sets up a space with rooms, calendar and
+          Don't wait for an invite. {PLATFORM_NAME} Hosting sets up a space with rooms, calendar and moderation
-          moderation in about a minute.
+          in about a minute.
         {/if}
       </p>
       <Button class="button button-primary button-sm" onclick={openCreate}>

src/app/title.ts

@@ -7,8 +7,6 @@ import {app, profiles, rooms} from "@app/core"
 import {PLATFORM_NAME} from "@app/env"
 import {decodeRelay} from "@app/relays"
 
-const FALLBACK_APP_NAME = "Flotilla"
-
 const staticTitles = new Map<string, string>([
   ["/", "Redirecting"],
   ["/home", "Home"],
@@ -108,9 +106,7 @@ export const makeTitle = (...parts: Array<string | undefined>) =>
   parts
     .map(part => part?.trim() || "")
     .filter(identity)
-    .join(" · ") ||
+    .join(" · ") || PLATFORM_NAME
-  PLATFORM_NAME ||
-  FALLBACK_APP_NAME
 
 export const getPageTitle = ({page, pubkey}: PageTitleContext) => {
   const routeId = page.route.id || ""