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, 45 insertions, 0 deletions

diff --git a/crates/detect-core/src/manifests/github-copilot.toml b/crates/detect-core/src/manifests/github-copilot.toml
new file mode 100644
index 0000000..57fafdd
--- /dev/null
+++ b/crates/detect-core/src/manifests/github-copilot.toml
@@ -0,0 +1,45 @@
+id = "copilot"
+version = "2026.08.29.1"
+min_engine_version = 1
+updated_at = "2026-08-29T00:00:00Z"
+aliases = ["github-copilot", "ghcs"]
+
+[[rules]]
+id = "selection_blocker"
+state = "blocked"
+priority = 300
+region = "whole_recent"
+visible_blocker = true
+all = [
+  { any = [
+    { contains = ["esc to cancel"] },
+    { contains = ["esc cancel"] },
+  ] },
+  { any = [
+    { contains = ["enter to select"] },
+    { contains = ["enter to confirm"] },
+    { contains = ["enter to submit"] },
+    { contains = ["enter accept"] },
+  ] },
+]
+
+[[rules]]
+id = "background_agents_working"
+state = "working"
+priority = 110
+region = "bottom_non_empty_lines(6)"
+visible_working = true
+line_regex = ['^\s*◎\s+Waiting for background agents(?:\s|·|$)']
+
+[[rules]]
+id = "working_cancel_hint"
+state = "working"
+priority = 100
+region = "whole_recent"
+visible_working = true
+any = [
+  { contains = ["esc to cancel"] },
+  { contains = ["esc cancel"] },
+  { contains = ["esc again to cancel"] },
+  { contains = ["esc interrupt"] }
+]