chore: rename project quicnprotochat -> quicproquo (binaries: qpq)

Rename the entire workspace:
- Crate packages: quicnprotochat-{core,proto,server,client,gui,p2p,mobile} -> quicproquo-*
- Binary names: quicnprotochat -> qpq, quicnprotochat-server -> qpq-server,
  quicnprotochat-gui -> qpq-gui
- Default files: *-state.bin -> qpq-state.bin, *-server.toml -> qpq-server.toml,
  *.db -> qpq.db
- Environment variable prefix: QUICNPROTOCHAT_* -> QPQ_*
- App identifier: chat.quicnproto.gui -> chat.quicproquo.gui
- Proto package: quicnprotochat.bench -> quicproquo.bench
- All documentation, Docker, CI, and script references updated

HKDF domain-separation strings and P2P ALPN remain unchanged for
backward compatibility with existing encrypted state and wire protocol.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

crates/quicproquo-server/migrations/001_initial.sql

@@ -0,0 +1,47 @@
+CREATE TABLE IF NOT EXISTS key_packages (
+    id           INTEGER PRIMARY KEY AUTOINCREMENT,
+    identity_key BLOB NOT NULL,
+    package_data BLOB NOT NULL,
+    created_at   INTEGER DEFAULT (strftime('%s','now'))
+);
+
+CREATE TABLE IF NOT EXISTS deliveries (
+    id            INTEGER PRIMARY KEY AUTOINCREMENT,
+    recipient_key BLOB NOT NULL,
+    channel_id    BLOB NOT NULL DEFAULT X'',
+    payload       BLOB NOT NULL,
+    created_at    INTEGER DEFAULT (strftime('%s','now'))
+);
+
+CREATE TABLE IF NOT EXISTS hybrid_keys (
+    identity_key      BLOB PRIMARY KEY,
+    hybrid_public_key BLOB NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_kp_identity
+    ON key_packages(identity_key);
+
+CREATE INDEX IF NOT EXISTS idx_del_recipient_channel
+    ON deliveries(recipient_key, channel_id);
+
+CREATE TABLE IF NOT EXISTS server_setup (
+    id         INTEGER PRIMARY KEY CHECK (id = 1),
+    setup_data BLOB NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS users (
+    username      TEXT PRIMARY KEY,
+    opaque_record BLOB NOT NULL,
+    created_at    INTEGER DEFAULT (strftime('%s','now'))
+);
+
+CREATE TABLE IF NOT EXISTS user_identity_keys (
+    username     TEXT PRIMARY KEY,
+    identity_key BLOB NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS endpoints (
+    identity_key BLOB PRIMARY KEY,
+    node_addr    BLOB NOT NULL,
+    updated_at   INTEGER DEFAULT (strftime('%s','now'))
+);

crates/quicproquo-server/migrations/002_add_seq.sql

@@ -0,0 +1,21 @@
+-- Migration 002: add per-inbox delivery sequence numbers.
+--
+-- Adds a `seq` column to the deliveries table and a separate counter table
+-- that tracks the next sequence number per (recipient_key, channel_id) inbox.
+-- The counter is atomically incremented on each enqueue via an UPSERT so
+-- sequence numbers are gapless even under concurrent inserts.
+--
+-- Requires SQLite >= 3.35 (RETURNING clause support; available on Ubuntu 22.04+).
+
+ALTER TABLE deliveries ADD COLUMN seq INTEGER NOT NULL DEFAULT 0;
+
+CREATE TABLE IF NOT EXISTS delivery_seq_counters (
+    recipient_key BLOB    NOT NULL,
+    channel_id    BLOB    NOT NULL,
+    next_seq      INTEGER NOT NULL DEFAULT 0,
+    PRIMARY KEY (recipient_key, channel_id)
+);
+
+-- Index lets ORDER BY seq queries use an index scan instead of a sort.
+CREATE INDEX IF NOT EXISTS idx_del_seq
+    ON deliveries (recipient_key, channel_id, seq);

crates/quicproquo-server/migrations/003_channels.sql

@@ -0,0 +1,13 @@
+-- Migration 003: 1:1 DM channels.
+-- channel_id is 16 bytes (UUID); member_a and member_b are identity keys in sorted order.
+-- Unique on (member_a, member_b) prevents duplicate channels between the same pair.
+
+CREATE TABLE IF NOT EXISTS channels (
+    channel_id BLOB PRIMARY KEY,
+    member_a   BLOB NOT NULL,
+    member_b   BLOB NOT NULL,
+    UNIQUE(member_a, member_b)
+);
+
+CREATE INDEX IF NOT EXISTS idx_channels_members
+    ON channels(member_a, member_b);

crates/quicproquo-server/migrations/004_federation.sql

@@ -0,0 +1,16 @@
+-- 004_federation.sql: Federation support tables.
+
+-- Map identity keys to their home server domain.
+-- Used for routing: if a recipient's home_server != local domain, relay via federation.
+CREATE TABLE IF NOT EXISTS identity_home_servers (
+    identity_key BLOB PRIMARY KEY,
+    home_server  TEXT NOT NULL,
+    updated_at   INTEGER NOT NULL
+);
+
+-- Known federation peers (other quicnprotochat servers).
+CREATE TABLE IF NOT EXISTS federation_peers (
+    domain    TEXT PRIMARY KEY,
+    last_seen INTEGER NOT NULL,
+    is_active INTEGER NOT NULL DEFAULT 1
+);