[michielbdejong]

Follow-up to #1754 and #1757. Stacked on #1757 (claude/route-write-grant-ui).

Before this PR, editing an Installation's config so that a write target's config: key named another resource left the plugin's write on the old parent and gave the new parent nothing. Route writes to the new parent were then refused.

What changes

• Detect: routeWriteConfigChange(grants, savedConfig, editedConfig) (lib) lists the route-grant targets whose resolved parent changes, and throws UnresolvedWriteTargetError when the edit leaves one unresolved.
• Approve again: Save on the Installation page opens "Move incoming items". It reuses Approve route writes in the install review (#1717 follow-up, includes #1742) #1757's RouteWriteApproval with the new parent marked New, unchecked by default.
• Move: saveInstallationConfig (lib) saves the config and rewrites route-writes in grants. When approved, it gives write on the new parent and takes it back from the old one, in commits the signed-in agent signs. When saved unchecked, it drops the route grant and every right it came with, as declining an upgrade's new targets does.
• Refuse: a config that leaves a target unresolved can't be saved. Save is disabled, a note names the key, and the lib throws before committing anything.
• A config change that moves nothing is saved as before.

Screenshots

Taken against a --features plugin-routes server at --plugin-routes read-write, with the #1754 inbox fixture published from a draft, installed with the route grant, then its inbox changed from an Inbox folder to an Archive folder. After approving, the server reported write on Archive for the plugin agent and no longer on Inbox. Files (local): followup-1758-move-approval-{desktop,mobile}.png, followup-1758-unresolved-{desktop,mobile}.png.

The [i18n-404] after "Pinned to" in the unresolved screenshot was already there: it is the "from …" line in a conditional with nested elements, which this PR doesn't touch.

Tests

• plugin-route-grant.test.ts: detecting a move (including a config stored as a JSON string), approving it (rights moved, grant kept, commits signed by the installer), declining it (grant and rights dropped), an unresolved target (nothing committed, no agent fetch), and a change that moves nothing.
• RouteWriteMoveDialog.test.tsx: New marker, unchecked default, save approved and declined.
• cargo test -p atomic-server --lib with and without plugin-routes, clippy both ways, data-browser and lib typecheck.

Closes #1758

🤖 Generated with Claude Code

[michielbdejong]

Merge-risk triage (2026-09-28). This is a read-only review of this PR's own diff. The rule it applies: nothing that works today may break for existing users or clients, and new behaviour is added alongside the old. The stack is being rebased onto develop as one chain before merging, so line references are against the current stacked base.

Verdict: SAFE

The config Save button now goes through saveInstallationConfig, which without a route grant does the same as before (set config, save()), with no agent fetch and no rights change.

🤖 Generated with Claude Code

[michielbdejong]

Closing as part of the plugin-host stack cleanup (Q-101): not needed by atomic-plugins now. See the inventory at #1726 (comment). The branch is kept, and pin candidates are unaffected. Closed by Claude (VPS coordinator) on behalf of Michiel.