docs: plan the post-boot hygiene tasks

neogaia was installed from a configuration written before the hardware
existed, so several things are now knowably wrong rather than guessed.

Adopt the upstream hardware profile for this laptop, which fixes deep
sleep, thermal management and the touchpad driver. Bound the store, the
retained generations and the boot menu, none of which have a limit today.
Declare the commit identity, which currently lives only in one checkout.

Grow the EFI system partition, which holds around seven generations at
its present size and cannot be enlarged in place, since the encrypted
container immediately behind it would have to be relocated. That makes a
reimage the only practical route, and the cheapest moment for one is now.
It doubles as the reproducibility test of the install documentation.

.claude/tasks/0016-esp-resize-and-reimage.md

@@ -0,0 +1,27 @@
+---
+blocked-by: [0013-nixos-hardware-profile, 0014-nix-store-housekeeping, 0015-git-module]
+---
+
+## What to build
+
+Grow `neogaia`'s EFI system partition and reimage the laptop from the finished configuration.
+
+The partition is 512 MiB today, holding about seven generations at roughly 70 MiB of kernel and initrd apiece, and this `Host` runs a large third-party kernel. It grows to 2 GiB, which holds around 28 — comfortably past the 15 that are retained, at a cost of 0.3% of a 512 GB disk.
+
+It cannot be grown in place: it sits first on the disk, starting at sector 2048 with the encrypted container immediately behind it, so enlarging it means moving that container's start offset. An encrypted volume's start cannot be relocated without rewriting its entire payload, which here is over 500 GiB. A reimage is the only practical route, and it is cheapest now — the machine is days old and holds around 3 GiB, of which 136 MiB is user data.
+
+The blocking tasks are sequencing rather than strict dependency. Only the partition size is technically required; installing from the merged configuration means wiping once and booting into a machine that is already correct.
+
+This reimage is also the reproducibility test of the install documentation. The first install was performed while writing it; performing it a second time against the current configuration is what proves it is a procedure rather than a record of one improvised session.
+
+One thing must be true before the disk is erased: every branch worth keeping has to exist on the remote, because work that lives only on this disk dies with it.
+
+## Acceptance criteria
+
+- [ ] The `Host`'s disk layout declares a 2 GiB EFI system partition
+- [ ] Every local branch worth keeping exists on the remote before the disk is erased
+- [ ] The reimage is performed from the merged configuration, following the existing install documentation
+- [ ] The install documentation is corrected wherever the procedure diverged from what it describes
+- [ ] Manual confirmation: the machine boots, the encrypted root unlocks, and console login succeeds
+- [ ] Manual confirmation: reported free space on the boot partition is consistent with its 2 GiB size, resolving the discrepancy observed before the reimage — where a 512 MiB partition reported 1022 MiB
+- [ ] The project's agent instructions record that a flake only sees git-tracked files, so an untracked file is invisible to evaluation