chore: restore product scaffold to rollback baseline

Cargo.toml

@@ -12,15 +12,15 @@
 #   crates/chanora_audio/        — capture, DSP, Opus, jitter, mixer
 #   crates/chanora_storage/      — bookmarks, settings, identity refs
 #   crates/chanora_diagnostics/  — logs, redaction, export
+#   crates/chanora_server_prefetch — server-resolution prefetch cache/policy
 #   crates/chanora_bridge/       — Flutter/Rust typed DTOs + glue
 #
 # The Flutter app is not part of this Cargo workspace; it is owned by
 # Gradle / Xcode / Flutter tooling under apps/chanora_flutter/.
 #
-# Non-promotion reminder (proof-of-concept-plan.md §4): nothing under
-# poc/ is product code. The crates here are blank scaffolds at this
-# stage; promotion of PoC code happens crate-by-crate with explicit
-# audit-trail commits.
+# Proof-of-concept spikes are archived separately in the private
+# chanoraapp/chanora-poc repository. Promotion of PoC findings into
+# product code happens crate-by-crate with explicit audit-trail commits.
 
 [workspace]
 resolver = "2"
@@ -31,20 +31,12 @@ members = [
     "crates/chanora_audio",
     "crates/chanora_storage",
     "crates/chanora_diagnostics",
+    "crates/chanora_server_prefetch",
     "crates/chanora_bridge",
     "crates/chanora_resolver",
 ]
 
-# Excludes: the PoC trees stay outside the product workspace so that
-# `cargo check --workspace` at the root does not pull in PoC builds.
 exclude = [
-    "poc/tsclientlib-connect-spike",
-    "poc/secure-storage-spike",
-    "poc/sqlite-storage-spike",
-    "poc/diagnostics-redaction-spike",
-    "poc/audio-capture-playback-spike",
-    "poc/audio-capture-playback-android-spike",
-    "poc/flutter_rust_bridge_hello",
     "apps/chanora_flutter",
 ]