merge origin/main into feat/wf5-securestorage

Brings MOSAIC_GIT_IDENTITY (per-seat git authorship) onto the delivery
branch, which had none of it. The branch carried W-F7's FLEET_SEAT seam in
the same launcher file; the two auto-merged cleanly.

Three single-hunk conflicts resolved:
- pr-merge.sh: kept branch policy allowing main OR next (next is the
  release stream).
- test-ci-queue-wait-tristate.sh: kept the branch's 4 added merge-readiness
  assertions; merge base and main both had zero, so nothing of main's is
  reverted.
- package.json test:framework-shell: union of both enumerations, 50 entries,
  no test dropped from either side. Picks up main's test-start-agent-session.sh
  and test-fleet-units.sh, which are the guards for the identity key.

packages/mosaic/framework/runtime/claude/settings.json

@@ -11,6 +11,16 @@
             "timeout": 10
           }
         ]
+      },
+      {
+        "matcher": "Bash",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "~/.config/mosaic/tools/git/wrapper-guard.sh",
+            "timeout": 10
+          }
+        ]
       }
     ],
     "PostToolUse": [