docs(skills): document the action and component nav item types (#14138)

* docs(skills): document the action and component nav item types

The objectstack-ui Navigation Item Types table listed 7 of the 9 live
discriminated-union members; `action` and `component` had no row, so an
author reading the published skill could not discover either target.

Funded within the file's token ceiling (headroom was 0) by deleting two
Common Pitfalls entries that carry no fact the file does not state better
elsewhere:

- pitfall 1 restated the Data Source best-practice block verbatim (and that
  block is the richer of the two -- it also names automatic CRUD);
- pitfall 4 ("always add a quick filter") is superseded by the ADR-0047
  userFilters section, which prescribes the opposite default: omit
  `userFilters` when unsure, most views need no filter elements at all.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Msg17tAHJ3jVTYFgHydCm2

* chore(gates): ratchet the skill-identifier-liveness Leg 2 gap to zero

The recorded NavItemVariant gap of 2 (action, component) is closed by the
table rows in the previous commit; the gate refuses an improvement that
leaves budget behind for a later edit to spend silently.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Msg17tAHJ3jVTYFgHydCm2

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: claude[bot]

scripts/skill-identifier-liveness-ledger.json

@@ -31,10 +31,5 @@
       "note": "Live in ../objectui at packages/plugin-gantt/src/GanttView.tsx, same shift-band prop family as dayStart. Unreachable from this repo's index for the same reason."
     }
   ],
-  "leg2Gaps": {
-    "navigation-item-types": [
-      "action",
-      "component"
-    ]
-  }
+  "leg2Gaps": {}
 }

skills/objectstack-ui/SKILL.md

@@ -641,6 +641,8 @@ export const CrmApp = App.create({
 | `report`    | `reportName`, `label`, `icon`                 | Link to a report |
 | `page`      | `pageName`, `label`, `icon`                   | Link to a custom Page (`type: 'home' | 'list' | ...`) |
 | `url`       | `url`, `label`, `icon`                        | External or custom URL |
+| `action`    | `actionDef` (`{ actionName, params? }`), `label`, `icon` | Run an action instead of navigating |
+| `component` | `componentRef`, `params?`, `label`, `icon`    | Built-in platform component; `componentRef` is a colon-joined registry key (`metadata:resource`), `params` become props |
 | `separator` | —                                             | Visual separator |
 
 > **`requiresObject` / `requiresService`:** Use these on any item that
@@ -2053,23 +2055,15 @@ the selected row in `list_item` contexts.
 
 ## Common Pitfalls
 
-1. **Using `provider: 'api'` when `provider: 'object'` is available.**
-   Object provider gives you free filtering, sorting, pagination, and
-   real-time updates.
-
-2. **Putting too many columns in a grid view.**
+1. **Putting too many columns in a grid view.**
    Users rarely need more than 6–8 columns visible by default. Use `hidden`
    for secondary columns.
 
-3. **Forgetting `link: true` on the primary column.**
+2. **Forgetting `link: true` on the primary column.**
    The first meaningful column (usually the name/subject) should be the
    navigation link to the record detail.
 
-4. **Not setting quick filters.**
-   Quick filters dramatically improve usability. Always add at least a
-   "My Records" filter using `$currentUser`.
-
-5. **Putting widget grid placement in `position`.**
+3. **Putting widget grid placement in `position`.**
    The grid-placement field is `layout: { x, y, w, h }` — `position` is not a
    widget key and the closed schema REJECTS it by name (it was silently
    dropped before protocol 17). `layout` is optional: omit it and the widget