Hold a message in the server's queue until the time you asked for

Scheduled send, which the README listed as needing server support that
Stalwart has had all along. The delay cannot be asked for directly --
RFC 8621 makes `sendAt` read-only and server-derived -- so it goes on the
envelope as an RFC 4865 `HOLDUNTIL` parameter, and the server reports back
the time it settled on.

Stalwart advertises this in the *account* capability, not the session-level
one (which is empty): `maxDelayedSend` of thirty days and `FUTURERELEASE`
among its `submissionExtensions`. The composer offers scheduling only when
both are there, and never offers a time the server would refuse.

A held message goes to a Scheduled folder rather than Sent, because
`onSuccessUpdateEmail` would otherwise file it as sent the moment the
submission is created, and it has not been sent. Nothing moves it out when
the hold expires, so the folder is reconciled on the way in: released
messages to Sent, cancelled ones back to Drafts. Cancelling uses a separate
`Email/set` rather than `onSuccessUpdateEmail`, whose key Stalwart reads as
an Email id and not, as the RFC says, a submission id.

The mock grows the whole lifecycle, and learns to resolve creation
references while it is there -- it had been quietly declining to create any
submission at all, since sending names its message as `#m`. Because
Stalwart's own `futureRelease` setting defaults to off and then drops the
hold in silence, `npm run dev:mock:no-future-release` reproduces that.

Verified end to end against the mock; not yet against the live server.

README.md

@@ -52,7 +52,7 @@ seconds of downtime with nothing lost.
 - Invitations: `.ics` parts render as an invite card with **Yes/Maybe/No** RSVP (via `CalendarEvent/parse` + iTIP); `.vcf` parts offer *Add to contacts*; `List-Unsubscribe` one-click
 - **Right-click anyone named in a message** — sender, To, Cc, Bcc, Reply-To — to add them to the address book (the contact editor opens prefilled, with the display name split into first/last), edit them if they are already known, write to them, or copy the address
 - Search with Gmail operators (`from:`, `to:`, `subject:`, `has:attachment`, `is:unread`, `is:starred`, `in:`, `label:`, `before:`, `after:`, `larger:`, `smaller:` …) plus an advanced-search panel
-- Composer: multiple floating/minimised/maximised composers, rich-text editor (formatting, lists, links, colours, images pasted/dropped inline, emoji), plain-text mode, recipient chips with autocomplete from **contacts, the directory (GAL) and recent recipients**, multiple identities with HTML signatures, Cc/Bcc, priority, read-receipt request, templates/canned responses, attachment upload with progress, drag & drop, attachment reminder, **undo send**, autosaved drafts, reply/reply-all/forward with quoting and inline images preserved
+- Composer: multiple floating/minimised/maximised composers, rich-text editor (formatting, lists, links, colours, images pasted/dropped inline, emoji), plain-text mode, recipient chips with autocomplete from **contacts, the directory (GAL) and recent recipients**, multiple identities with HTML signatures, Cc/Bcc, priority, read-receipt request, templates/canned responses, attachment upload with progress, drag & drop, attachment reminder, **undo send**, **scheduled send** (quick picks or an exact date and time; the message waits in the server's queue, so it goes out whether or not ihasmail is open), autosaved drafts, reply/reply-all/forward with quoting and inline images preserved
 - Live updates via JMAP push (EventSource proxied server-side) with polling fallback; desktop notifications, sound, title/favicon unread badge
 - A–Z folder list with Inbox pinned on top (other special folders mixed in), subfolders nested and collapsed by default with chevrons in their own gutter so every icon lines up; unread folders are bold (a parent is bold when a subfolder has unread mail); right-click a folder to mark it read *including subfolders*, create/rename/hide/share/empty, quota bar, Outlook-style module bar (Mail · Calendar · Contacts · Files) at the bottom of the pane, multi-account switching for shared accounts
 
@@ -121,6 +121,10 @@ npm run dev:mock       # mock on :8788, server on :8080, Vite on :5173
 # the same, with the mock impersonating Stalwart 0.15 instead of 0.16
 npm run dev:mock:legacy
 
+# the same, with the mock advertising FUTURERELEASE but dropping every hold —
+# the shape of a real server whose `futureRelease` setting was never turned on
+npm run dev:mock:no-future-release
+
 npm run typecheck      # tsc for both packages
 npm test               # vitest (web) + node:test (server)
 npm run build          # web/dist + server/dist
@@ -192,13 +196,14 @@ Both backends have now met a real server of their own generation.
 - **HTML signatures** — Stalwart caps a signature at 2047 **bytes** (`value.len() < 2048` on a Rust string, so UTF-8 bytes, not characters). ihasmail compacts pasted HTML, moves images to Files and, if still too large, keeps the full signature in Files behind a short marker; other clients see a text fallback. Confirmed live on 0.15.5 (2026-08-24): oversized, non-ASCII and inline-image signatures all save, and a test message arrived intact at Gmail with the logo inline.
 - **Files on Stalwart before 0.16** — three things differ there, none of which the server reports as an error. (Confirmed live on 0.15.5 before the upgrade. The live instance now runs 0.16.19, where folder creation, upload, rename, move and delete are also confirmed; the older path is kept for anyone still on 0.15.x and covered by `npm run dev:mock:legacy`.) `FileNode/query` masks its results to non-containers, so it returns files and **never folders**; `nodeType` does not exist, and sending it fails the create outright (a directory is instead a node with no file properties at all); and rights are only `mayRead`/`mayWrite`/`mayShare`, so the finer-grained `mayDelete`/`mayRename` the UI gates on are absent. ihasmail detects the older server by the absence of `urn:stalwart:jmap`, lists the tree through `FileNode/get` instead of query, shapes creates accordingly, and widens the old rights. Upload, folder creation, listing, rename, move and delete are all confirmed live on 0.15.5 (2026-08-24).
 - **Self-service credentials** — the **0.15.x REST path was confirmed live** against Stalwart 0.15.5 (2026-08-24): password change, app passwords, and enabling and disabling 2FA, on a real mailbox. The **0.16 registry path is confirmed live** against Stalwart 0.16.19 (2026-08-25): app passwords created and revoked, password changed, 2FA enabled and disabled, with the browser session surviving the switch to an app password. The mock enforces the same rules either way (current password required, password policy, a TOTP code on every request once 2FA is on, app passwords exempt from it). Password changes are refused by Stalwart for accounts backed by an external directory (LDAP/SQL/OIDC); the server's own message is shown when that happens.
+- **Scheduled send needs one setting turned on, and says nothing when it is off.** Stalwart advertises the delay in the account's `urn:ietf:params:jmap:submission` capability — `maxDelayedSend: 2592000` (30 days) and `FUTURERELEASE` among its `submissionExtensions`, and note it is the *account* capability, not the session-level one, which is empty. But the MTA only honours a hold when `futureRelease` is set under the session's MTA extensions, and [that setting defaults to `false`](https://stalw.art/docs/ref/object/mta-extensions/). With it off, Stalwart takes the `HOLDUNTIL` parameter, skips the hold and sends the message immediately **without an error** — the capability still says thirty days. So set `futureRelease` (to the longest hold you want to allow) before relying on this; a value shorter than 30 days is fine, and a request past it is refused honestly, with a `forbiddenMailFrom` naming the limit. `npm run dev:mock:no-future-release` reproduces the silent-drop case. ihasmail asks for the delay the way JMAP requires — a `HOLDUNTIL` parameter on the envelope's `mailFrom`, since RFC 8621 makes `sendAt` read-only and server-derived — and files the held message in a **Scheduled** folder, because `onSuccessUpdateEmail` would otherwise drop it in Sent the moment the submission is created. Nothing moves it out when the hold expires, so ihasmail reconciles the folder on the way in: released messages to Sent, cancelled ones back to Drafts. Three fixes this depends on landed in **0.16.17**, below the live instance's 0.16.19: `HOLDUNTIL` taking RFC 3339 date-times again (0.16.16 had it wanting Unix timestamps), `EmailSubmission/query` on `undoStatus` agreeing with `/get` about held submissions, and `EmailSubmission/get` without `ids` iterating the right index. **Not yet exercised against the live server** — verified end to end against the mock only.
 - Recurring events: colour/category/edit/delete apply to the whole series (per-occurrence overrides aren't supported by the server yet).
 - Editable date boxes are always Gregorian and in Latin digits, even for locales whose *display* uses another calendar or numbering system (`fa-IR`, `th-TH`, `ar-EG`) — they keep the locale's field order and separator, but a Buddhist-era year in a text box does not round-trip against the Gregorian calendar grid. Non-Gregorian calendar support is not implemented.
 - The account locale is read from `x:AccountSettings/get`, whose permission the built-in user role has, falling back to `x:Account/get` (which needs the admin-only `sysAccountGet`). Both are Stalwart 0.16 methods: **on older servers neither is reachable** — they do not implement the registry and reject a request that so much as names the `urn:stalwart:jmap` capability — so there the locale still falls back to the browser's and can be chosen by hand. Confirmed working on the live 0.16.19 instance, where the account locale now resolves for an ordinary user.
 
 ## Roadmap / not yet
 
-- Snooze and scheduled send (needs server-side support)
+- Snooze (nothing in JMAP or Stalwart supports it, and ihasmail never stores a password, so nothing could act on a mailbox while you are away)
 - Read-receipt (MDN) sending, S/MIME / OpenPGP
 - Translations (strings are English-only for now)