Add auto-summary settings

CHANGELOG.md

@@ -6,6 +6,24 @@ loosely follows [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+### Added
+- Auto-summarization for top-level agent tabs. patterm now loads
+  `$XDG_CONFIG_HOME/patterm/settings.json`, enables Codex-based
+  summaries by default (`gpt-5.4-mini`; OpenCode defaults to
+  `opencode-go/minimax-m2.7`), and can run Codex, OpenCode, or opt-in
+  Claude summarizers with configurable model names. Summary
+  attempts are armed by meaningful human input, wait for recent output
+  to go quiet, and respect a minimum cadence so unchanged tabs are not
+  summarized on a timer. The active thread summary appears under the
+  top tab title and in the sidebar below the Agent Tree section.
+- Settings overlay reachable from the command palette via
+  `Open Settings`. The searchable Settings picker opens
+  `Agents / Auto-summarization`, where users can enable/disable
+  summaries, choose provider, edit provider model names, cycle cadence,
+  test the selected summarizer (`patterm okay`), summarize the current
+  top-level agent immediately, and explicitly save or cancel draft
+  settings changes.
+
 ### Changed
 - Command palette UX overhaul. The single flat list grew section
   bands (`── Focused ──`, `── Open ──`, `── Spawn ──`, `── Quit ──`)