fix(lint): walk kanban.titleField at calendar's level in the list-view position table

`POSITIONS` declares, per view face, which field-reference keys are walked and
at what level. `kanban` was the only item-titled face with no `titleField` row,
and since the key became authorable on `KanbanConfigSchema` a misspelt field
name cleared the schema door, was walked by nothing, and left the board titled
from the ADR-0079 display-name chain instead of the field the author named.

The level is `warning`, the one `calendar` takes: the key is OPTIONAL on both
schemas, and objectui's board (`resolveKanbanTitleField` -> `rec[titleField]`
-> `getRecordDisplayName`) renders every card regardless. `timeline` and
`gantt` spell the key required and take `error`; they are not the siblings this
row copies.

Claude-Session: https://claude.ai/code/session_01JbZnqu8bt6YqfJsr9vaFb3
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

.changeset/18565-kanban-titlefield-position.md

@@ -0,0 +1,23 @@
+---
+"@objectstack/lint": minor
+---
+
+fix(lint): `list-view-field-unknown` walks `kanban.titleField` — the one item-titled face the position table never listed (#18565)
+
+Clause-②: no
+
+`POSITIONS` in `validate-list-view-field-refs.ts` declares, per view face, which field-reference keys are walked and at what level, and `kanban` was the only item-titled face with no `titleField` row. From #16894 the key is authorable on `KanbanConfigSchema`, so from that release a misspelt field name cleared the schema door, was walked by nothing, and the board fell back to the ADR-0079 record display name — a title the author did not ask for, on a board that renders correctly, with no gate reporting the miss. The byte-identical typo one block away on `calendar` or `timeline` was reported.
+
+Measured on this branch, one list view carrying every walked position, one mutation at a time:
+
+| probe | before | after |
+|:--|:--|:--|
+| `kanban.titleField` naming a field that does not exist | silent | `warning` `list-view-field-unknown` at `views[0].list.kanban.titleField` |
+| `kanban.titleField` naming a real field | silent | silent |
+| the other 51 walked positions | 51 reported, 1 silent (this one) | the same 51, each at its same severity |
+
+Over the repo's own example apps (`app-crm`, `app-todo`, `app-multi-package`, `app-showcase`) the findings count is **0 before and 0 after**: five kanban blocks are authored there and none carries `titleField`, so nothing existing starts reporting. Injecting `titleField: 'zz_no_such_field'` into those same boards flips 0 → 1 warning in `app-crm` and `app-showcase`.
+
+**`warning`, the level `calendar` takes — not the level of the two siblings that spell the key required.** `KanbanConfigSchema` declares `titleField` OPTIONAL (#16894 copied `CalendarConfigSchema` for this exact key and names `TimelineConfigSchema` / `GanttConfigSchema`, the two that spell it required, as the siblings it deliberately does not copy), and the board resolves an unresolvable name through the ADR-0079 display-name chain: measured in objectui `dda8f3815`, `resolveKanbanTitleField` returns the written name, the card reads `rec[titleField]`, finds nothing and falls to `getRecordDisplayName`. Every card still renders — the warning tier's own case in this rule's module note ("the renderer drops one decoration and renders the rest: an optional colour / title / tooltip / cover binding"), where `kanban.groupByField` is the error tier's, collapsing every card into one uncolumned lane.
+
+No rule id, no severity and no message shape changes for any other position; `list-view-field-unknown` gains one more place it can be reported from.

packages/lint/src/validate-list-view-field-refs.ts

@@ -322,7 +322,21 @@ const POSITIONS: Record<string, BlockPositions> = {
   kanban: {
     // `columns` here are the fields shown ON a card, not the board's columns:
     // a stale entry leaves one blank line on the card and the board renders.
-    scalars: { groupByField: 'error', summarizeField: 'warning' },
+    //
+    // [#18565] `titleField` takes CALENDAR's level, not the level of the two
+    // siblings that spell the key required. `KanbanConfigSchema` declares it
+    // OPTIONAL (#16894, which copied `CalendarConfigSchema` for this exact key
+    // and names `TimelineConfigSchema` / `GanttConfigSchema` — the two whose
+    // rows below read `error` — as the siblings it deliberately does NOT
+    // copy), and the board resolves a name no record carries through the
+    // ADR-0079 display-name chain: measured in objectui `dda8f3815`,
+    // `resolveKanbanTitleField` returns the written name, the card reads
+    // `rec[titleField]`, finds nothing and falls to `getRecordDisplayName`.
+    // Every card still renders, titled from a value the author did not ask
+    // for — the warning tier's own case (one decoration dropped, the rest
+    // rendered), where `groupByField` above is the error tier's (every card
+    // collapses into one uncolumned lane).
+    scalars: { groupByField: 'error', summarizeField: 'warning', titleField: 'warning' },
     lists: { columns: 'warning' },
   },
   calendar: {