rclaude: launch path no longer forces --continue; resume path keeps it

Conflating launch and resume was wrong: tmux already provides 'reattach to
the live conversation' (named session keyed by dir). Adding --continue to
the launch path also caused surprise replays of stale conversations and
clashed with other claude processes holding the same on-disk session.

- launch (rclaude HOST DIR): plain 'claude' — fresh session
- transport-drop reattach: tmux session reattach (automatic, same command)
- explicit on-disk resume: 'rclaude resume <pattern>' — sets RCLAUDE_RESUME=1
  when re-execing, which adds --continue to the launch invocation

bin/rclaude

@@ -152,8 +152,10 @@ cmd_resume() {
             fi
             ;;
         disk)
-            # Spawn a fresh tmux + claude --continue at the recorded cwd.
+            # Spawn tmux + claude --continue at the recorded cwd. The env var
-            exec "$0" "$_host" "$_target"
+            # tells the launch path below to add --continue (it doesn't by
+            # default, since --continue is the explicit-resume behavior).
+            RCLAUDE_RESUME=1 exec "$0" "$_host" "$_target"
             ;;
     esac
 }
@@ -216,8 +218,15 @@ esac
 build_inner() {
     # Single-line, single-quote-safe. Variables prefixed with rc_ to avoid
     # collision with anything in the user's shell.
+    #
+    # Note: launch path uses plain `claude` (fresh session). Reattach to a
+    # live conversation is handled by tmux (named session keyed on dir, so
+    # re-running rclaude in the same dir reattaches). Disk-resume is the
+    # explicit `rclaude resume <pattern>` subcommand.
+    _resume_flag=""
+    [ "${RCLAUDE_RESUME:-0}" = "1" ] && _resume_flag="--continue"
     printf '%s' \
-        "cd ${1} && rc_t=\$(date +%s); claude --continue ${flag}; rc_ec=\$?; " \
+        "cd ${1} && rc_t=\$(date +%s); claude ${_resume_flag} ${flag}; rc_ec=\$?; " \
         "rc_e=\$(date +%s); rc_d=\$((rc_e - rc_t)); " \
         "if [ \$rc_ec -ne 0 ] || [ \$rc_d -lt 2 ]; then " \
         "printf '\\n[rclaude] claude exited in %ds with code %d\\n' \$rc_d \$rc_ec; " \