feat(tmux-util): add find subcommand

tmux-util find <pattern> walks every pane across every session, queries each pane's foreground command (`#{pane_current_command}`), and prints the location of any pane whose command matches the pattern. Output format: `<session>:<window>.<pane> <command>`, one per line.

Pattern is a basic ERE (passed through `grep -E`), so anchors and alternation work. Substring matching is the common case.

Exit code:
- 0 with output: matches found
- 1 with no output: no matches (lets you script around it)
- 2 with usage on stderr: missing or empty pattern

7 new tests cover Normal cases (single match, multi-match across sessions, format verification) and Boundary cases (no matches, no sessions, missing pattern, empty pattern). fake-tmux now parses pid:cmd entries in the state file so panes can carry a synthetic command name. Total suite: 39 tests, all green.

1 files changed, 27 insertions, 1 deletions

diff --git a/dotfiles/common/.local/bin/tmux-util b/dotfiles/common/.local/bin/tmux-util
index 4a7b596..5e0ce85 100755
--- a/dotfiles/common/.local/bin/tmux-util
+++ b/dotfiles/common/.local/bin/tmux-util
@@ -36,6 +36,29 @@ EOF
 }
 
 # -----------------------------------------------------------------------------
+# find
+# -----------------------------------------------------------------------------
+
+cmd_find() {
+    local pattern="${1:-}"
+    if [ -z "$pattern" ]; then
+        echo "tmux-util find: missing pattern" >&2
+        echo "Usage: tmux-util find <pattern>" >&2
+        return 2
+    fi
+
+    local matches
+    matches=$(tmux list-panes -a \
+        -F '#{session_name}:#{window_index}.#{pane_index} #{pane_current_command}' \
+        2>/dev/null | grep -E "$pattern" || true)
+
+    if [ -z "$matches" ]; then
+        return 1
+    fi
+    echo "$matches"
+}
+
+# -----------------------------------------------------------------------------
 # go
 # -----------------------------------------------------------------------------
 
@@ -178,7 +201,10 @@ main() {
         go)
             cmd_go "$@"
             ;;
-        pick|find|rename)
+        find)
+            cmd_find "$@"
+            ;;
+        pick|rename)
             echo "tmux-util: subcommand '$sub' is not implemented yet" >&2
             return 2
             ;;