Update project documentation and code comments to remove platform-specific references

Refactor documentation files and code comments to remove references to Replit, specific task numbers, and other platform-specific identifiers.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 77cfe984-2c65-4152-bb7a-0df28274fe66
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: fa18e5d4-a810-4bd5-8cde-2a60d64d9e3f
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/c3c252e4-c83d-40ca-9fff-99a3ea60701e/77cfe984-2c65-4152-bb7a-0df28274fe66/kI0sxlu
Replit-Helium-Checkpoint-Created: true

.gitignore

@@ -28,7 +28,7 @@ service-account*.json
 # Legacy uploaded session assets (superseded by object storage)
 attached_assets/
 
-# Hosted-platform configs and agent state (kept locally, never in git)
+# Local-only platform / agent state (never in git)
 .replit
 .replitignore
 replit.nix
@@ -39,6 +39,7 @@ replit.md
 .cache/
 .config/
 .upm/
+**/.replit-artifact/
 
 # Local object storage (used by the local FS storage driver)
 storage/