Remove deprecated files and enhance subscription stability

- Deleted obsolete files including ALL_FIXES.md, MESSAGE_QUEUE_FIX.md, PUBLISHER_FIX.md, and others to streamline the codebase.
- Implemented critical fixes for subscription stability, ensuring receiver channels are consumed and preventing drops.
- Introduced per-subscription consumer goroutines to enhance event delivery and prevent message queue overflow.
- Updated documentation to reflect changes and provide clear testing guidelines for subscription stability.
- Bumped version to v0.26.3 to signify these important updates.

.claude/settings.local.json

@@ -15,7 +15,9 @@
       "Bash(md5sum:*)",
       "Bash(timeout 3 bash -c 'echo [\\\"\"REQ\\\"\",\\\"\"test456\\\"\",{\\\"\"kinds\\\"\":[1],\\\"\"limit\\\"\":10}] | websocat ws://localhost:3334')",
       "Bash(printf:*)",
-      "Bash(websocat:*)"
+      "Bash(websocat:*)",
+      "Bash(go test:*)",
+      "Bash(timeout 180 go test:*)"
     ],
     "deny": [],
     "ask": []