chore(gitignore): untrack ephemeral state + ignore large local artifacts

- git rm --cached: .inbox_baseline.txt, .loop_log.txt (coordination ephemeral)
- Add: .agents/, .codex/, agent_chat/state/, graphify/, graphify-out/ (local state/tool)
- Add: webbrowser (11M PostScript artifact), deploy/installer/lea_python_embed_working.tgz (37M)
- Add: benchmarks/computer_use/predictions/ (generated), **/instance/*.db.bak* (runtime backup)

.gitignore

@@ -144,3 +144,23 @@ deploy/installer/python-3.12.8-embed-amd64.zip
 # Artefacts de build installateur (EXE compilés + staging) — non versionnés
 deploy/releases/*.exe
 deploy/build/
+# Embed tgz working (37M, local build artifact)
+deploy/installer/lea_python_embed_working.tgz
+
+# Agent/Codex state (local, session-specific)
+.agents/
+.codex/
+agent_chat/state/
+
+# Graphify tool + generated output (1.2G)
+graphify/
+graphify-out/
+
+# Local PostScript artifact (webbrowser = 11M DSC)
+webbrowser
+
+# Bench predictions (generated, not source)
+benchmarks/computer_use/predictions/
+
+# DB backups (instance level, runtime artifact)
+**/instance/*.db.bak*