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>"`.

agent/cairnobs-agent/src/config.rs

@@ -77,7 +77,7 @@ pub enum SourceConfig {
     // Dead-code-on-default-build, same reasoning as EventLog/Etw below:
     // these fields are only read by the `file-tail`-gated arm in
     // spawn_source (main.rs), which doesn't exist in the default build
-    // (`default = ["journald"]`). Pre-existing gap from Phase 0 — CLAUDE.md
+    // (`default = ["journald"]`). Pre-existing gap from Phase 0 — PROJECT-SPEC.md
     // mandates plain `cargo clippy --all-targets -- -D warnings` (no
     // --all-features), which this broke silently since only
     // --all-features clippy was ever actually run.
@@ -202,7 +202,7 @@ impl Default for MetricsConfig {
 /// way. Kept as a small hand-rolled parser rather than pulling in a
 /// duration-parsing crate for this one field -- this is the
 /// statically-linked edge agent every "no glibc runtime deps" constraint
-/// in CLAUDE.md is about keeping lean, and the grammar needed here is a
+/// in PROJECT-SPEC.md is about keeping lean, and the grammar needed here is a
 /// handful of lines.
 fn deserialize_duration<'de, D>(deserializer: D) -> Result<Duration, D::Error>
 where