docs(skill): document sendNotification action (7 actions total) + CLI support

- skill: SKILL.md (7 actions in description + routing table entry), action-types.md
  (new section #4 sendNotification: config keys, variables, system-in-app semantics),
  automation-guide.md/cli-reference.md (--to-user/--title/--message/--severity/--path),
  development.md (7 actions), metadata.json abstract
- cli: action add --type sendNotification now builds config from granular flags
  (toUserId/title/message/severity/path); ACTION_TYPES includes sendNotification;
  live-verified via workflow create + action add + delete

.agents/skills/inkreach-teable/SKILL.md

@@ -4,8 +4,8 @@ description: >-
   Operate a deployed inkreach-teable instance (a Teable fork with a self-built
   automation engine). Configure tables, fields, records, views, and automations
   (8 triggers incl. recordCreated/Updated/Condition, formSubmitted, scheduledTime,
-  buttonClick, webhook; 6 actions: script, sendEmail, httpRequest, createRecord,
-  updateRecord, getRecords), plus secrets, execution history, and dynamic plugins
+  buttonClick, webhook; 7 actions: script, sendEmail, httpRequest, createRecord,
+  updateRecord, getRecords, sendNotification), plus secrets, execution history, and dynamic plugins
   (install/uninstall, base-level mount nodes, developer whitelist, CSP apiOrigins).
   Trigger when the user wants to manage tables/fields/records/views, build or
   configure automations/workflows, set up button-field triggers, schedule jobs,
@@ -69,7 +69,7 @@ Respond in the user's language. Keep answers concise and action-oriented.
 | Receive external HTTP | Trigger `webhook`; fire via `fire webhook` | Expecting auth (backend ignores it) |
 | Schedule recurring job | Trigger `scheduledTime` (only type+interval work) | Passing triggerTime/weekdays (backend ignores) |
 | Per-row AI / transformation | Action `script` reading `triggerInput` | Manual row-by-row via record API |
-| Send notification | Action `sendEmail` or `httpRequest` | — |
+| Send notification | Action `sendNotification` (system in-app) | `sendEmail` (needs SMTP) unless email is truly required |
 | Add a custom UI / view / panel | Plugins: `plugin install --position base` | Manually editing DB rows |
 | Allow a user to upload plugins | Plugins: `plugin dev allow <userIdOrEmail>` (admin only) | — |
 | Plugin needs external API access | Plugins: declare `apiOrigins` in `plugin.json` manifest | Editing CSP in next.config.js (global) |
@@ -152,7 +152,7 @@ These differ from official teable and from the (stale) `docs/automation/triggers
 Files in `api-reference/`, read when you need exact config formats:
 
 - **[trigger-types.md](api-reference/trigger-types.md)** — all 8 triggers: type string, config keys, output variables.
-- **[action-types.md](api-reference/action-types.md)** — all 6 actions: config keys, sandbox globals, variable references.
+- **[action-types.md](api-reference/action-types.md)** — all 7 actions: config keys, sandbox globals, variable references.
 - **[field-types.md](api-reference/field-types.md)** — Teable field types, aliases, and option shapes (incl. Button field with `workflowId`).
 
 ## 7. Instance Access