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.

proto/sentry/logs/v1/logs.pb.go

@@ -100,7 +100,7 @@ type LogRecord struct {
 	Severity Severity `protobuf:"varint,4,opt,name=severity,proto3,enum=sentry.logs.v1.Severity" json:"severity,omitempty"`
 	// Original, unparsed log line. Always populated, even when structured
 	// fields below are also present, per the schema-on-read fallback
-	// requirement in CLAUDE.md.
+	// requirement in PROJECT-SPEC.md.
 	Message string `protobuf:"bytes,5,opt,name=message,proto3" json:"message,omitempty"`
 	// Structured fields extracted by the agent's parser (e.g. RFC 5424
 	// syslog header fields), plus source-provided fields (e.g. Windows

proto/sentry/logs/v1/logs.proto

@@ -43,7 +43,7 @@ message LogRecord {
 
   // Original, unparsed log line. Always populated, even when structured
   // fields below are also present, per the schema-on-read fallback
-  // requirement in CLAUDE.md.
+  // requirement in PROJECT-SPEC.md.
   string message = 5;
 
   // Structured fields extracted by the agent's parser (e.g. RFC 5424