Telegram/Discord: honor outbound mediaMaxMb uploads (#38065)

* Telegram: default media cap to 100MB

* Telegram: honor outbound mediaMaxMb

* Discord: add shared media upload cap

* Discord: pass mediaMaxMb to outbound sends

* Telegram: cover outbound media cap sends

* Discord: cover media upload cap config

* Docs: update Telegram media cap guide

* Docs: update Telegram config reference

* Changelog: note media upload cap fix

* Docs: note Discord upload cap behavior

docs/channels/discord.md

@@ -1194,6 +1194,7 @@ High-signal Discord fields:
 - delivery: `textChunkLimit`, `chunkMode`, `maxLinesPerMessage`
 - streaming: `streaming` (legacy alias: `streamMode`), `draftChunk`, `blockStreaming`, `blockStreamingCoalesce`
 - media/retry: `mediaMaxMb`, `retry`
+  - `mediaMaxMb` caps outbound Discord uploads (default: `8MB`)
 - actions: `actions.*`
 - presence: `activity`, `status`, `activityType`, `activityUrl`
 - UI: `ui.components.accentColor`

docs/channels/telegram.md

@@ -724,7 +724,7 @@ curl "https://api.telegram.org/bot<bot_token>/getUpdates"
   <Accordion title="Limits, retry, and CLI targets">
     - `channels.telegram.textChunkLimit` default is 4000.
     - `channels.telegram.chunkMode="newline"` prefers paragraph boundaries (blank lines) before length splitting.
-    - `channels.telegram.mediaMaxMb` (default 5) caps inbound Telegram media download/processing size.
+    - `channels.telegram.mediaMaxMb` (default 100) caps inbound and outbound Telegram media size.
     - `channels.telegram.timeoutSeconds` overrides Telegram API client timeout (if unset, grammY default applies).
     - group context history uses `channels.telegram.historyLimit` or `messages.groupChat.historyLimit` (default 50); `0` disables.
     - DM history controls:
@@ -873,7 +873,7 @@ Primary reference:
 - `channels.telegram.chunkMode`: `length` (default) or `newline` to split on blank lines (paragraph boundaries) before length chunking.
 - `channels.telegram.linkPreview`: toggle link previews for outbound messages (default: true).
 - `channels.telegram.streaming`: `off | partial | block | progress` (live stream preview; default: `partial`; `progress` maps to `partial`; `block` is legacy preview mode compatibility). In DMs, `partial` uses native `sendMessageDraft` when available.
-- `channels.telegram.mediaMaxMb`: inbound Telegram media download/processing cap (MB).
+- `channels.telegram.mediaMaxMb`: inbound/outbound Telegram media cap (MB, default: 100).
 - `channels.telegram.retry`: retry policy for Telegram send helpers (CLI/tools/actions) on recoverable outbound API errors (attempts, minDelayMs, maxDelayMs, jitter).
 - `channels.telegram.network.autoSelectFamily`: override Node autoSelectFamily (true=enable, false=disable). Defaults to enabled on Node 22+, with WSL2 defaulting to disabled.
 - `channels.telegram.network.dnsResultOrder`: override DNS result order (`ipv4first` or `verbatim`). Defaults to `ipv4first` on Node 22+.