fix(tsconfig): drop deprecated baseUrl so shared-ui components compile under TypeScript 6

TypeScript 6 deprecates baseUrl (TS5101), and svelte-preprocess promotes
that deprecation into a hard build error. It only bit the two apps that
import packages/shared-ui components - shared-ui has no tsconfig of its
own, so svelte-preprocess walks up to the ROOT tsconfig (the one with
baseUrl) when compiling ConfidencePill.svelte and
ToggleHeader__PromptOrPackage--Icons.svelte, failing the shell and
response-reviewer dev builds. Apps that don't pull in shared-ui compiled
against their own baseUrl-free tsconfigs and never noticed.

Fix is the TS6-idiomatic one, not the ignoreDeprecations escape hatch:
remove baseUrl and let paths resolve relative to the tsconfig, which the
root config's ./-prefixed paths already did. splash/tsconfig.json gets
the same treatment with its paths entries ./-prefixed to match.

Verified: shell and response-reviewer rsbuild builds are clean, and the
tree-wide typecheck stays green.

Files changed:
- tsconfig.json
- splash/tsconfig.json

TS6 upgrade fallout from 68670bc, surfaced by the first dev-server run
since.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: mpstaton

splash/tsconfig.json

@@ -3,16 +3,15 @@
   "include": [".astro/types.d.ts", "**/*"],
   "exclude": ["dist"],
   "compilerOptions": {
-    "baseUrl": ".",
     "paths": {
-      "@/*": ["src/*"],
-      "@components/*": ["src/components/*"],
-      "@layouts/*": ["src/layouts/*"],
-      "@loaders/*": ["src/loaders/*"],
-      "@lib/*": ["src/lib/*"],
-      "@styles/*": ["src/styles/*"],
-      "@content/*": ["src/content/*"],
-      "@pages/*": ["src/pages/*"]
+      "@/*": ["./src/*"],
+      "@components/*": ["./src/components/*"],
+      "@layouts/*": ["./src/layouts/*"],
+      "@loaders/*": ["./src/loaders/*"],
+      "@lib/*": ["./src/lib/*"],
+      "@styles/*": ["./src/styles/*"],
+      "@content/*": ["./src/content/*"],
+      "@pages/*": ["./src/pages/*"]
     }
   }
 }

tsconfig.json

@@ -14,7 +14,6 @@
       "strict": true,
       "noUnusedLocals": true,
       "noUnusedParameters": true,
-      "baseUrl": ".",
       "paths": {
         "@/*": ["./src/*"],
         "@packages/*": ["./packages/*/src"],