[lawrencecchen]

Summary

Fixes the tip arch red from #32213 (c9835aa, the agent banner): over its parent it added app_lines +278 to CmuxNextApp. After #32414 lands (the #32127 fix), this is the one rise left on the tip.

Takes back #32213: only where its code lives. Its Needs you banner rules leave the App for a package; the feature stays the same for the person.

The lines #32213 put in the App are mostly wiring that has to stay, so its rules move together with the system notifier they post through. A new CmuxNextNotifications target (layer ui) holds:

• AttentionBanners: the Needs you banner rules cmux NEXT: a banner with Show for a tab an agent marked (carry of #24345) #32213 wrote as a NotificationCenterService extension (a changed mark list posts or withdraws banners, the launch reconciliation of an earlier launch's banners, the policy arrival and decision, Show). NotificationCenterService is its AttentionBannerHost and keeps only what the App knows: its machines, windows and the marked-tab list.
• DesktopNotifier (and its incognito strings), whose attention category and retained-banner read cmux NEXT: a banner with Show for a tab an agent marked (carry of #24345) #32213 added, and the permission types it answers notifications.status / notifications.request with. NotificationsControl's control methods stay in the App.

The strings move with their code, every locale included (the App catalogs only lose those keys). Tests now call service.attention.… instead of the old service.attention… methods.

Testing

• python3 scripts/cmux-next/arch-ratchet.py --base c9835aa239ce^ --head 9a043f986d2: app_lines was +193 on the base tip (cmux NEXT: a banner with Show for a tab an agent marked (carry of #24345) #32213 alone: +278); with this PR it is -324. This commit alone is app_lines -517. No other row rises.
• python3 scripts/cmux-next/prepush-gate.py: no new violations. arch_rules/layer_gate.py: ok. scripts/lint-ios-package-conventions.sh: ok. scripts/lint-xcstrings.py on the three changed catalogs: passed.
• Fleet cmux-ci compile-check --ref 8522f32f328 --app: passed at 8522f32 (job adc1765dc79f44a33cc2147a).
• Fleet suites (package-test-lane.sh suite Packages/macOS/CmuxNext ...): all 9 suites passed at 8522f32 (job 856dfeed60965ef8eca2b27f, aws-m4pro-8): AttentionBannerTests 11 tests, AttentionSnapshotTests 8, AttentionTabsTests, AgentPaneAttentionTabsTests 5, DesktopNotifierSystemCenterTests 5, IncognitoSurfacesTests, NotificationBannerContentTests, NotificationPreviewTests, NotificationsControlTests.

The head 9a043f9 differs from 8522f32 only in plans/cmux-next/swift-linux-inventory.md, put back to the base content (a generated file the "no new generated files" guard refuses in a PR; no check needs it current). The fleet runs above therefore cover the head's Swift.

Observed / Not run

Observed: the ratchet and gate runs, the fleet app compile, and the fleet suites above (#32213's own: AttentionBannerTests, AttentionSnapshotTests, AttentionTabsTests, AgentPaneAttentionTabsTests; and the moved notifier's: DesktopNotifierSystemCenterTests, IncognitoSurfacesTests, NotificationBannerContentTests, NotificationPreviewTests, NotificationsControlTests). Not run: a tagged build with a real Needs you banner and its Show button. That path is read, not run.

Changelog

none

Proof

No capture: no UI change; code moves between targets and keeps its behavior.

[github-actions]

cmux status _{(one comment, edited in place; each line is updated by the job that owns it)}

Review 9a043f9: HQ feed card · gallery before/after runs · checks

App of this head (app.zip, kept 1 day)

gh workflow run reload-build.yml -R manaflow-ai/cmux --ref feat-cmux-next -f tag=pr32438 -f ref=fix/base-red-banner-arch -f platform=macos -f backend_mode=local

Shipped in:

• cmux NEXT nightly 1.0.0-nightly.4148415549501 (4729158bf9)
• cmux NEXT nightly 1.0.0-nightly.4148563744401 (dc06451eaf)
• cmux NEXT nightly 1.0.0-nightly.4148851513401 (736181335c)
• cmux NEXT nightly 1.0.0-nightly.4149093743601 (d6fe77646f)

[lawrencecchen]

Review (claude-review-subagent): SHIP at 9a043f9

Reviewed read-only: 4a1c444..9a043f9 against the culprit c9835aa. 9a043f9 differs from 8522f32 only in plans/cmux-next/swift-linux-inventory.md, and that file is again the same as the base. So the fleet compile (adc1765dc79f44a33cc2147a) and the 9 suites (856dfeed60965ef8eca2b27f) at 8522f32 cover the head's Swift.

Findings (none blocking):

• Behavior is the same. AttentionBanners.marksChanged / decision / arrival / post / show have the same logic as the removed NotificationCenterService extension. Only these changed: services -> host witnesses (attentionTabs, attentionDaemons, isIncognito, which read the same services paths), attentionSeen -> seen, and attentionBanners -> posted. The reconcile Task is the same, with [weak self, desktop] and it reads posted after the await. Before, the service deinit cancelled it. Now the AttentionBanners deinit cancels it, and that runs when the service is released, so the lifetime is the same. decision returns nil only when the host is gone. post() binds a strong host first, so that nil path cannot occur there.
• No retain cycle. The service holds the lazy attention strongly, the back reference is weak, and the Task captures self weakly and only desktop strongly.
• DesktopNotifier.swift is byte-identical to the base copy apart from the package keywords. Its package API names only same-module types or types from package import AppKit / UserNotifications. AttentionBannerHost names only types from its package imports (AgentPane, Daemon, DaemonService, Feed, Settings). The internal NotificationCenterService witnesses are sufficient for the package protocol.
• Strings: a JSON comparison shows 8 Localizable keys and 2 NotificationsPanel keys moved, with identical content, into the new target's tables of the same name. App catalogs: no other key was added, removed or changed. Every String(localized:) in CmuxNextNotifications resolves in its own catalogs, and the incognito strings are in the NotificationsPanel table. No App or test source still uses a moved key.
• git grep finds no remaining references to the removed names. Every App or test file that names DesktopNotifier / NotificationPermission* imports CmuxNextNotifications.
• Only CmuxNextApp and CmuxNextAppTests depend on CmuxNextNotifications. Its dependencies cannot reach the App, so there is no cycle. layer_gate: ok. arch-ratchet at --base c9835aa^: app_lines -324 and no row rises. At the PR base: -517. prepush-gate: no new violations. lint-ios-package-conventions: ok (NotificationPermissionStrings is internal, so the struct form is fine).
• Notes: the guardrail asks you to tell PL-arch about the architecture-layers.json row. The ratchet suggests lowering arch-ratchet.json (--update), which this PR does not need. Not run: a tagged build with a real Needs you banner and its Show button. Also, ci-target-graph.json does not yet list the new target, but routing for an unmapped package path falls back to every tier, so no coverage is skipped.