Point the @ alias at a relative path, and drop baseUrl

TypeScript 7 removes `baseUrl` outright and refuses a non-relative entry
in `paths`, so the typecheck stops on tsconfig.json before it reaches a
line of our code. A leading `./` says the same thing without it: paths
resolve against the tsconfig's own directory, which is what `baseUrl:
"."` was there to arrange.

Nothing here waits for the upgrade. Relative paths without a baseUrl
have been the supported spelling since 4.4, so this typechecks the same
under 5.9.3 today as it will under 7. Vite resolves `@` from its own
alias in vite.config.ts and never read this.

With this in, 7.0.2 typechecks both workspaces clean -- the two
tsconfig errors were all that stood in the way, not the first two of
many.

web/tsconfig.json

@@ -16,8 +16,7 @@
     "allowImportingTsExtensions": true,
     "noEmit": true,
     "types": ["vite/client"],
-    "baseUrl": ".",
+    "paths": { "@/*": ["./src/*"] }
-    "paths": { "@/*": ["src/*"] }
   },
   "include": ["src", "vite.config.ts"]
 }