fix: use canonical dogfood seat identity (#1490)

Co-authored-by: marcie <[email protected]>

README.md

@@ -221,18 +221,19 @@ docker compose --profile stack up -d
 
 The optional dogfood overlay gives one dedicated in-stack agent a writable stack
 worktree and its own read-only credential slot. It does not mount the fleet brain or
-any other seat. Prepare a `next`-based worktree and an unprivileged `stack-dogfood`
-seat outside the container, then set these paths in `.env`:
+any other seat. Prepare a `next`-based worktree and an unprivileged
+`code-dogfood-01` functional seat outside the container, then set these paths in
+`.env`:
 
 ```dotenv
 MOSAIC_DOGFOOD_WORKTREE=/path/to/mosaic-stack-worktrees/dogfood-1487
 MOSAIC_DOGFOOD_COMMON_GIT_DIR=/path/to/mosaic-stack/.git
-MOSAIC_DOGFOOD_SEAT_HOME=/path/to/.mosaic/fleet/agents/stack-dogfood
+MOSAIC_DOGFOOD_SEAT_HOME=/path/to/.mosaic/fleet/agents/code-dogfood-01
 ```
 
 The common Git directory must match the worktree's `.git` pointer. The seat home
 must contain only that seat's credential at
-`secrets/gitea-mosaicstack-stack-dogfood.token`. Never place the token value in
+`secrets/gitea-mosaicstack-code-dogfood-01.token`. Never place the token value in
 `.env`. Start the overlay with:
 
 ```bash
@@ -245,7 +246,7 @@ docker compose \
 The overlay removes the general shell tool for every session, including admins.
 File tools stay inside the mounted checkout. Two dedicated delivery tools stage
 explicit paths, run the CI queue guard, push through `git-credential-mosaic`, and
-open PRs through `pr-create.sh`. They resolve only the `stack-dogfood` slot and fail
+open PRs through `pr-create.sh`. They resolve only the `code-dogfood-01` slot and fail
 if it is absent. The overlay enables Docker's init process so the R4 helper can
 establish the gateway's seat lineage below PID 1.