refactor(plugins/platforms): migrate IRC + Teams to new env_enablement + cron_deliver hooks

Adopt the generic platform-plugin hooks landed in the preceding commit
so IRC and Teams get env-only config detection and cron home-channel
delivery without living in cron/scheduler.py's hardcoded sets.

IRC (plugins/platforms/irc/):
- adapter.py: new _env_enablement() seeds server, channel, port,
  nickname, use_tls, server_password, nickserv_password, and a
  home_channel dict into PlatformConfig on env-only setups.
  IRC_HOME_CHANNEL defaults to IRC_CHANNEL so deliver=irc cron jobs
  route to the joined channel by default.
- adapter.py: register_platform() gains env_enablement_fn=_env_enablement
  and cron_deliver_env_var='IRC_HOME_CHANNEL'.
- plugin.yaml: rich requires_env / optional_env with description,
  prompt, password, url for every IRC env var.  Hardcoded IRC entries
  in hermes_cli/config.py still win (back-compat), but the plugin now
  carries its own metadata.

Teams (plugins/platforms/teams/):
- adapter.py: new _env_enablement() seeds client_id, client_secret,
  tenant_id, port, and home_channel into PlatformConfig.  Closes the
  long-standing gap where TEAMS_HOME_CHANNEL was documented but never
  wired up.
- adapter.py: register_platform() gains env_enablement_fn=_env_enablement
  and cron_deliver_env_var='TEAMS_HOME_CHANNEL' — deliver=teams cron
  jobs now work.
- plugin.yaml: rich requires_env / optional_env with description,
  prompt, password, url for every Teams env var.  Surfaces them in
  'hermes config' UI for the first time (Teams had no OPTIONAL_ENV_VARS
  entries before this).

Zero behavior change for existing users: env_enablement_fn is only
called when env vars are set, and the registry's config-first-env-fallback
path in validate_config / is_connected is unchanged.

plugins/platforms/teams/plugin.yaml

@@ -1,4 +1,5 @@
 name: teams-platform
+label: Microsoft Teams
 kind: platform
 version: 1.0.0
 description: >
@@ -7,7 +8,41 @@ description: >
   between Teams chats (personal DMs, group chats, channel posts) and
   the Hermes agent. Supports Adaptive Card approval prompts.
 author: Aamir Jawaid
+# ``requires_env`` entries are surfaced in ``hermes config`` UI via the
+# platform-plugin env var injector in ``hermes_cli/config.py``.
 requires_env:
-  - TEAMS_CLIENT_ID
-  - TEAMS_CLIENT_SECRET
-  - TEAMS_TENANT_ID
+  - name: TEAMS_CLIENT_ID
+    description: "Azure AD application (Bot Framework) client ID"
+    prompt: "Teams / Azure AD client ID"
+    url: "https://portal.azure.com/"
+    password: false
+  - name: TEAMS_CLIENT_SECRET
+    description: "Azure AD application client secret"
+    prompt: "Teams / Azure AD client secret"
+    url: "https://portal.azure.com/"
+    password: true
+  - name: TEAMS_TENANT_ID
+    description: "Azure AD tenant ID hosting the bot application"
+    prompt: "Teams / Azure AD tenant ID"
+    password: false
+optional_env:
+  - name: TEAMS_PORT
+    description: "Webhook listen port (Bot Framework default: 3978)"
+    prompt: "Webhook port"
+    password: false
+  - name: TEAMS_ALLOWED_USERS
+    description: "Comma-separated Teams user IDs / UPNs allowed to talk to the bot"
+    prompt: "Allowed users (comma-separated)"
+    password: false
+  - name: TEAMS_ALLOW_ALL_USERS
+    description: "Allow any Teams user to trigger the bot (dev only)"
+    prompt: "Allow all users? (true/false)"
+    password: false
+  - name: TEAMS_HOME_CHANNEL
+    description: "Default chat/channel ID for cron / notification delivery"
+    prompt: "Home channel (or empty)"
+    password: false
+  - name: TEAMS_HOME_CHANNEL_NAME
+    description: "Display name for the Teams home channel"
+    prompt: "Home channel display name"
+    password: false