chore: rename quicproquo → quicprochat in Rust workspace

Rename all crate directories, package names, binary names, proto
package/module paths, ALPN strings, env var prefixes, config filenames,
mDNS service names, and plugin ABI symbols from quicproquo/qpq to
quicprochat/qpc.

crates/quicprochat-server/migrations/011_recovery_bundles.sql

@@ -0,0 +1,7 @@
+-- Recovery bundle storage: encrypted bundles keyed by token_hash.
+CREATE TABLE IF NOT EXISTS recovery_bundles (
+    token_hash BLOB PRIMARY KEY,
+    bundle     BLOB NOT NULL,
+    ttl_secs   INTEGER NOT NULL DEFAULT 0,
+    created_at INTEGER NOT NULL DEFAULT (strftime('%s', 'now'))
+);