Replace weak client-side ID generation with crypto-based collision-safe primitives

.github/copilot-instructions.md

@@ -10,6 +10,8 @@ Canonical repo policy lives in [../AGENTS.md](../AGENTS.md).
 
 If anything in this file conflicts with `AGENTS.md` or the canonical docs, the canonical docs win.
 
+Prefer Serena MCP whenever it can handle project activation, onboarding, file or symbol work, memory operations, refactors, edits, or shell execution. The brief Serena tool glossary lives in `AGENTS.md`; follow the project naming rules from there at the start of each chat.
+
 ## Copilot-specific notes
 
 - Keep the `applyTo` frontmatter so Copilot discovers this file automatically.

.serena/.gitignore

@@ -1 +1,4 @@
 /cache
+/project.local.yml
+# Ignore project.yml to allow multi-worktree support without conflicts. Each worktree can have its own project.yml file.
+/project.yml