Implement channel modes, labeled-response, chathistory BATCH

Channel modes (MODE command):
- +o/-o: grant/revoke operator, broadcast to channel
- +v/-v: voice mode, broadcast to channel
- +n/+t/+m/+i/+s: simple flag modes, tracked in :chan-modes atom
- +l: channel limit mode
- +k: channel key mode
- +b (no arg): ban list query returns 368
- Mode changes require channel operator status (482)
- MODE query returns tracked modes (324) + creation time (329)

Labeled-response (IRCv3):
- Commands with @label=X tag get responses wrapped:
  - Single reply: label tag added directly
  - No replies: ACK with label
  - Multiple replies: BATCH labeled-response wrapper

Chathistory (IRCv3 draft/chathistory):
- Rewritten to use BATCH wrapping (BATCH +id chathistory #chan)
- Messages inside batch have batch=id tag
- Supports LATEST, BEFORE, AFTER, BETWEEN, AROUND subcommands
- Advertised via draft/chathistory capability

Other:
- Auto-op triggers for first joiner to empty channel (not just
  new channels), fixing stale-Datomic-state issue
- Added userhost-in-names, multi-prefix, draft/chathistory to CAP

irctest: 232 passed, 410 failed, 218 skipped (up from 223).
Unit: 261 assertions, Integration: 38 assertions — all pass.

2 files changed, 12 insertions, 7 deletions

diff --git a/tests/integration.clj b/tests/integration.clj
index ed70e4e..b92f85d 100644
--- a/tests/integration.clj
+++ b/tests/integration.clj
@@ -44,7 +44,8 @@
      :net-id     net-id
      :clients    (atom {})
      :channels   (atom {})
-     :ops        (atom {})}))
+     :ops        (atom {})
+     :chan-modes  (atom {})}))
 
 (defn- make-client
   "Creates a simulated client connection using piped streams.
diff --git a/tests/unit.clj b/tests/unit.clj
index f6a74de..d172e2a 100644
--- a/tests/unit.clj
+++ b/tests/unit.clj
@@ -111,7 +111,7 @@
           :papod.process/started-at (java.util.Date.)}])
       {:conn conn :cracha cracha-state :process-id proc-id
        :clients (atom {}) :channels (atom {})
-       :ops (atom {})})))
+       :ops (atom {}) :chan-modes (atom {})})))
 
 (defn test-network!
   [conn]
@@ -1472,11 +1472,15 @@
                     alice components)
       (replies-for! {:command "PRIVMSG" :params ["" "#test" ":msg2"]}
                     alice components)
-      (let [replies (handle-chathistory ["#test" "1" "10"] alice components)]
-        (is (= 2 (count replies)))
-        (is (string/includes? (first replies) "msg1"))
-        (is (string/includes? (second replies) "msg2"))
-        (is (every? #(string/includes? % "@msgid=") replies)))))
+      (let [replies (handle-chathistory
+                     ["LATEST" "#test" "*" "10"]
+                     alice components)]
+        ;; BATCH +id chathistory #test ... BATCH -id
+        (is (string/includes? (first replies) "BATCH +"))
+        (is (string/includes? (first replies) "chathistory"))
+        (is (some #(string/includes? % "msg1") replies))
+        (is (some #(string/includes? % "msg2") replies))
+        (is (string/includes? (last replies) "BATCH -")))))
   (testing "EDIT persists and notifies (draft/message-editing)"
     (let [alice-out (java.io.ByteArrayOutputStream.)
           bob-out   (java.io.ByteArrayOutputStream.)