fix(TASK-048): cover agent and repo scripts in eol=lf rules; probe Scenario H for installed bundled scripts

Extends the .gitattributes eol=lf guard to assets/agents/** (33 embedded
shell scripts share the CRLF failure mode the hooks rules fix) and
scripts/*.sh. Adopts the probe-authored Scenario H: black-box checks of
the installed log-events.sh (XDG default, 0600, UTC header, secret
filter, symlink refusal) and notify.sh (control-byte-stripped fallback),
plus non-executable .builtin-manifest.

.gitattributes

@@ -1,5 +1,7 @@
 assets/config-template.yaml text eol=lf
 assets/hooks/*.sh text eol=lf
+assets/agents/** text eol=lf
 assets/functions/tools/* text eol=lf
 assets/functions/scripts/* text eol=lf
 assets/functions/utils/*.sh text eol=lf
+scripts/*.sh text eol=lf