Rename the project spec and update every reference to it

The charter file carried a tool-specific name while being the repository's own
document: mission, non-negotiable constraints, the pinned stack, repo
conventions and phase status, cited as authority by thirty files across the
agent, api, deploy, docs, search and terraform trees.

PROJECT-SPEC.md says what it is. All 42 references are updated in the same
commit, including the relative link in docs/status.md, so nothing points at a
filename that no longer exists.

agent/README.md

@@ -211,7 +211,7 @@ escalation, not a footnote: think about whether your environment wants
 the log-shipping agent running with that level of access before turning
 on the `etw` feature and an `[source] kind = "etw"` config. Event Log
 alone (no elevated privileges needed) covers the common case and is what
-Phase 1's exit criteria in `/CLAUDE.md` actually requires to be running.
+Phase 1's exit criteria in `/PROJECT-SPEC.md` actually requires to be running.
 
 Providers are configured by **GUID**, not friendly name — ETW's own API
 requires it. Look one up with `logman query providers "<Friendly Name>"`.