Send Message 1.0.0: one PIN, one place to send from; Slack 1.3.0 and ProdCom 1.4.0 become messaging providers

A new send-message module owns everything a dashboard sends: the PIN
(switchable off in admin), the unlock tokens, the Send message and Quick
replies tiles, the quick replies and quick emojis. It opens no upstream
connection of its own — it finds every module declaring
provides: ["messaging"] through the shell's module list and hands each
message to that module's POST /messaging/send over loopback, so Slack keeps
its one Slack connection and ProdCom its one ProdCom connection. Providers
check the browser's unlock token with GET /verify over loopback before
touching their upstream, so no browser on the network can post as the
location without having entered the PIN here.

Slack 1.3.0 is view-only plus reactions: the Sending group, PIN, send tiles
and quick replies are gone; it serves the messaging descriptor (channels as
recipients) and its reactions ride on the Send Message unlock. A layout's
old Send message / Quick replies tiles draw nothing until removed.

ProdCom 1.4.0 serves the descriptor as identities — only channels with
typingEnabled, since typed text goes out *as* a channel — and posts with
POST /api/v1/channels/{id}/send. Its tile is a click-to-target like Slack's
(accent stripe along the bottom), and typed entries carry a keyboard mark.

The tiles: click any Slack or ProdCom transcript to point sends there; a
Send as menu (only for platforms with identities, hidden otherwise) picks
the ProdCom channel to speak as; the choice is saved with the tile so named
layouts remember it. Wording follows the role — "Send message to #ops…" /
"Send message to ProdCom as FOH…". The PIN pad's dots ride on a real
numeric input so a phone's keyboard appears. Outcome is an icon beside
Send (check / blocked, five seconds, sentence as tooltip). A pill on the
box's bottom edge trades box height for rows of quick-emoji keys, a row
at a time; the single row scrolls sideways on a narrow tile with Send
pinned in place.

The module guide documents the provider contract and the page bus
(window.proddashMessaging + proddash:messaging:* events) the tiles share;
the ProdCom mock gained the send route.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

modules/prodcom-transcript/style.css

@@ -9,6 +9,28 @@
   flex-direction: column;
 }
 
+/* ── the send target ──
+   A click anywhere in the tile makes ProdCom the platform the Send Message
+   tiles send to. While it is, a 3px accent stripe runs along the bottom edge
+   of the tile body — drawn just inside our root, since the tile chrome
+   around it belongs to the shell. The others hint at it faintly on hover.
+   (The same mark as the Slack transcript's.) */
+[data-module="prodcom-transcript"] .pt-wrap::after {
+  content: "";
+  position: absolute;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  height: 3px;
+  background: var(--accent);
+  opacity: 0;
+  pointer-events: none;
+  z-index: 3;
+  transition: opacity 0.15s ease;
+}
+[data-module="prodcom-transcript"] .pt-wrap:hover::after { opacity: 0.3; }
+[data-module="prodcom-transcript"] .pt-wrap.is-target::after { opacity: 1; }
+
 /* ── channels button ──
    Icon-only; the count appears next to it while some channels are hidden. */
 
@@ -149,6 +171,15 @@
   overflow-wrap: break-word;
 }
 
+/* typed text (from a dashboard, or ProdCom's own box) and automations carry
+   their own mark in the picture slot; the text reads the same */
+[data-module="prodcom-transcript"] .pt-entry.typed .avatar,
+[data-module="prodcom-transcript"] .pt-entry.automation .avatar {
+  background: color-mix(in srgb, var(--ch, var(--muted)) 10%, transparent);
+  outline: 1px dashed color-mix(in srgb, var(--ch, var(--muted)) 55%, transparent);
+  outline-offset: -1px;
+}
+
 [data-module="prodcom-transcript"] .pt-entry.in-progress .text { color: var(--muted); }
 [data-module="prodcom-transcript"] .pt-entry.in-progress .text::after {
   content: "▍";