fix: keep SharePoint sync from blocking Home Manager activation

Preserve an in-flight timer job during service switching instead of restarting the oneshot and waiting for a potentially long synchronization. Herdr config installation succeeds; the activation timeout occurs later in reloadSystemd.

Verified the native keep-old behavior in pinned sources and a focused sd-switch dry run. Formatting, flake evaluation, Zenith build and whitespace checks passed. No live services changed; full activation remains user-controlled.

docs/constellation-work.md

@@ -169,9 +169,24 @@ the installed Herdr 0.9.0 default config and current upstream documentation.
 Interactive delivery through Kitty remains for user acceptance after activation.
 Reload Herdr with its existing Ctrl+B then Shift+R binding after activating Nix.
 Verification: repository formatting, rendered TOML parsing, flake evaluation,
-Zenith no-link system build and whitespace checking passed. No tests, activation
-or live Herdr session changes performed. Next input is the user's activation and
-combined feedback on pane/workspace movement, the pickers and agent jumps.
+Zenith no-link system build and whitespace checking passed. No tests or live Herdr
+session changes performed by the agent. The user's activation installed the Herdr
+config and preserved `config.toml.bak`, but Home Manager later timed out (below).
+After retrying activation, reload Herdr and gather combined feedback on
+pane/workspace movement, the pickers and agent jumps.
+
+Activation fix (2026-09-09): Home Manager's service switch stopped and restarted
+the running SharePoint oneshot, then waited until Home Manager's five-minute start
+timeout. Service-state inspection identified SharePoint as the sole pending user
+job; its oneshot start timeout is unlimited. This was not a Herdr file collision.
+Set `Unit.X-SwitchMethod = "keep-old"` in `sharepoint-reference.nix` so activation
+leaves an in-flight sync running; subsequent timer runs use the updated unit.
+Verified against pinned Home Manager/sd-switch source. Formatting, flake evaluation,
+Zenith build and whitespace checks passed; the focused sd-switch dry run reported
+`Keep active sharepoint-reference-sync.service`, with no restart planned. No live
+units were changed and no company content or credentials were read. The user must
+retry activation to verify the full switch; sync health/content completeness were
+not investigated.
 
 Mail search remains unresolved. The workbench's custom mail reader, inventory
 pilot, justfile and old README are archived; native Garden/kubectl/K9s now own the