Re-enabling type safety for the SPP

[lavocatt]

Our ts config has holes that we need to patch, sooner rather than later.

"strict": true is what we need really to early catch problematic bugs.

{
  "compilerOptions": {
    // ... paths and targets ...
    
    // THE MASTER SWITCH
    "strict": true, 

    // THE SAFETY NET FOR LIBRARIES
    "skipLibCheck": true,

    // Redundant flags you can remove (because 'strict: true' enables them):
    // "noImplicitAny": true,       <-- Removed (Included in strict)
    // "noImplicitReturns": true,   <-- strict doesn't cover this, KEEP IT
    // "noFallthroughCasesInSwitch": true, <-- strict doesn't cover this, KEEP IT
    
    // ... rest of config
  },
  "exclude": ["node_modules", "dist"]
}