initial dingger: tmux agent watcher with herdr's detection engine

extract detect-core from herdr's src/detect (engine + 22 manifests,
tests unchanged) and add the dingger binary: tmux capture-pane watcher,
process-tree agent identification, herdr's notification policy, embedded
notification sounds, @agent_state write-back, and catalog-based manifest
refresh. viewer screens are non-observations per the engine contract;
reviewed by a three-model panel (opus 5.5, gpt 6.1 sol, kimi k3) with
all confirmed findings applied as deletions.

1 files changed, 27 insertions, 0 deletions

diff --git a/crates/detect-core/src/manifests/pi.toml b/crates/detect-core/src/manifests/pi.toml
new file mode 100644
index 0000000..5ae51a8
--- /dev/null
+++ b/crates/detect-core/src/manifests/pi.toml
@@ -0,0 +1,27 @@
+id = "pi"
+version = "2026.10.01.1"
+min_engine_version = 1
+updated_at = "2026-10-01T00:00:00Z"
+aliases = ["herdr:pi"]
+
+[[rules]]
+id = "working_literal"
+state = "working"
+priority = 100
+region = "whole_recent"
+visible_working = true
+any = [
+  { contains = ["Working..."] },
+  { line_regex = ['^[⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏] Working$'] },
+]
+
+[[rules]]
+id = "working_border"
+state = "working"
+priority = 100
+region = "bottom_non_empty_lines(12)"
+visible_working = true
+any = [
+  { line_regex = ['^── [⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏] Working ─+$'] },
+  { line_regex = ['^[⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏] Working$'] },
+]