docs: remove references to deprecated show command

Update planning docs and audit tables to reflect the removal of
`lore show`:

- CLI_AUDIT.md: remove show row, renumber remaining entries
- plan-expose-discussion-ids.md: replace `show` with
  `issues <IID>`/`mrs <IID>`
- plan-expose-discussion-ids.feedback-3.md: replace `show` with
  "detail views"
- work-item-status-graphql.md: update example commands from
  `lore show issue 123` to `lore issues 123`

command-restructure/CLI_AUDIT.md

@@ -37,11 +37,10 @@
 | 29 | *help* | — | — | — | (clap built-in) |
 | | **Hidden/deprecated:** | | | | |
 | 30 | `list` | — | `<ENTITY>` | 14 | deprecated, use issues/mrs |
-| 31 | `show` | — | `<ENTITY> <IID>` | 1 | deprecated, use issues/mrs |
-| 32 | `auth-test` | — | — | 0 | deprecated, use auth |
-| 33 | `sync-status` | — | — | 0 | deprecated, use status |
-| 34 | `backup` | — | — | 0 | Stub (not implemented) |
-| 35 | `reset` | — | — | 1 | Stub (not implemented) |
+| 31 | `auth-test` | — | — | 0 | deprecated, use auth |
+| 32 | `sync-status` | — | — | 0 | deprecated, use status |
+| 33 | `backup` | — | — | 0 | Stub (not implemented) |
+| 34 | `reset` | — | — | 1 | Stub (not implemented) |
 
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