feat(clients): add safe client removal and archival

PLANS.md

@@ -266,7 +266,7 @@ Allowed status values: `NOT STARTED`, `IN PROGRESS`, `BLOCKED`, `DONE`.
 | M3        | DONE        | Locking, backups, atomic apply, and rollback engine  |
 | M4        | DONE        | Safe client creation                                 |
 | M5        | DONE        | Client detail, config export, and QR display         |
-| M6        | NOT STARTED | Safe client removal and archival                     |
+| M6        | DONE        | Safe client removal and archival                     |
 | M7        | NOT STARTED | Diagnostics engine and report                        |
 | M8        | NOT STARTED | Backup listing/restoration and audit log UX          |
 | M9        | NOT STARTED | TUI foundation, dashboard, and read-only screens     |
@@ -1635,6 +1635,20 @@ Use this template:
 - Suggested commit message: `feat(clients): add client details and secure config export`
 - Next milestone: M6
 
+## 2026-10-13 — M6 — DONE
+
+- Implemented: managed-only `remove NAME [--yes]`; safe interactive and noninteractive confirmation; exact public-key/marker/address block removal with post-lock identity revalidation; M3 transactional apply and rollback; restrictive timestamped archival of associated client artifacts; recovery handling for partial archival; and identity-protected, secret-free removal audit events.
+- Coordinator: `gpt-5.6-sol` (`high`)
+- Subagents: `milestone_worker` / `milestone_repairer`, `gpt-5.6-luna` (`medium`)
+- Repair cycles: 5
+- Sol review: replaced aliased and tautological focused tests with exact neighbor preservation and isolated identity cases; added privilege and confirmation gates; hardened archive source, owner, mode, hardlink, symlink, collision, partial-copy, partial-delete, and recovery handling; added post-lock metadata revalidation; protected audit files with restrictive ownership and opened-FD identity checks; preserved critical artifact-recovery status through server rollback; corrected test contamination, false original-path assertions, deterministic timestamps, and documentation ordering.
+- Verification: `bash -n wg-manager.sh`, `bash -n tests/run.sh`, `bash -n tests/helpers.sh`, `bash -n tests/mocks/bin/*`, `bash tests/run.sh remove-client`, `bash tests/run.sh remove-cancel`, `bash tests/run.sh remove-exact-block`, `bash tests/run.sh remove-rollback`, `bash tests/run.sh archive-client`, `bash tests/run.sh archive-path-safety`, `bash tests/run.sh remove-preserves-neighbors`, `bash tests/run.sh no-secret-logs`, `bash tests/run.sh`, `git diff --check`, permission, scope, and secret-pattern review.
+- Result: all required checks passed; remove-client/remove-cancel/remove-exact-block/remove-rollback/archive-client/archive-path-safety/remove-preserves-neighbors/no-secret-logs passed 17/16/5/7/58/31/5/41 assertions, and the full regression suite passed 461 assertions. Optional `shellcheck wg-manager.sh tests/*.sh tests/mocks/bin/*` was `SKIP` because ShellCheck is unavailable.
+- Decisions: none
+- Known limitations: real WireGuard, `/etc/wireguard`, networking, systemd, firewall, routes, sysctl, journal, real terminal confirmation, and deployment-server behavior were not accessed or tested; M6 verification is fixture- and mock-based as required. Permanent purge is intentionally not implemented.
+- Suggested commit message: `feat(clients): add safe client removal and archival`
+- Next milestone: M7
+
 # 8. Final completion rule
 
 The MVP is complete only when: