Group six more clusters out of web/src/lib

Takes the flat module count from 66 to 42, continuing what admin/ and
calendar/ started.

  lib/mailbox/  archiveDate, emptyFolder, folderMove, labelTree,
                mailboxName, mailboxRoute
  lib/sieve/    sieve, sieveApply, sieveFolders
  lib/input/    keyboard, swipe, touch, listSelection, dropUpload
  lib/notify/   notify, webpush, webpushEnable
  lib/sw/       swCache, swFacts, staleBuild
  lib/text/     html, markdown, text, emlName

FOUR THINGS THE FILENAMES GET WRONG, each checked by reading the file
rather than trusting what it is called:

  - appFolder is not a mailbox. It is the `ihasmail` folder in JMAP
    *Files*, where the client keeps signature images and synced settings.
    It stays flat.
  - format holds no formatting of text. It re-exports the date and clock
    formatters, so it belongs with dates/datetime, not with text/.
  - preview is the file viewer deciding what it can show without
    downloading, and source is where to point someone asking for this
    instance's AGPL source. Neither is about text.
  - notify is not Web Push. It is the tab title, the favicon badge and
    the new-mail sound -- in-app notification, which is why it sits with
    webpush rather than under sw/ with the service worker's own concerns.

threadScroll stays flat too: it decides where a conversation opens, which
is view state rather than a gesture, and input/ is honest only if
everything in it interprets something the reader did.

No behavior change. Almost every reference was on the @/ alias; eight
relative imports in files that did not move, or that moved away from a
sibling, needed rewriting by hand.

web/src/views/settings/__tests__/filters-unsaved-guard.test.tsx

@@ -5,7 +5,7 @@ import { FiltersSettings } from "../FiltersSettings";
 import { ConfirmHost } from "@/ui/dialog";
 import { useSieve } from "@/store/sieve";
 import { hasUnsavedChanges } from "@/lib/unsavedChanges";
-import { newRule, rulesToSieve } from "@/lib/sieve";
+import { newRule, rulesToSieve } from "@/lib/sieve/sieve";
 
 (globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
 

web/src/views/settings/__tests__/rule-dialog-header.test.tsx

@@ -2,7 +2,7 @@ import { act } from "react";
 import { createRoot, type Root } from "react-dom/client";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { RuleDialog } from "../RuleDialog";
-import { newRule } from "@/lib/sieve";
+import { newRule } from "@/lib/sieve/sieve";
 
 (globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;
 

web/src/views/settings/__tests__/rule-drag-reorder.test.tsx

@@ -3,7 +3,7 @@ import { createRoot, type Root } from "react-dom/client";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { FiltersSettings } from "../FiltersSettings";
 import { useSieve } from "@/store/sieve";
-import { newRule, rulesToSieve } from "@/lib/sieve";
+import { newRule, rulesToSieve } from "@/lib/sieve/sieve";
 
 (globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true;