docs(fork): record upstreamed divergences and prune their entries

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>

Author: yordis

docs/fork/0001-file-explorer-mention-actions.md

@@ -2,9 +2,10 @@
 
 This directory tracks everything this fork carries that is not in upstream
 [pingdotgg/t3code](https://github.com/pingdotgg/t3code). One numbered entry per
-divergence, newest last. When upstream ships an equivalent, update the status
-here and note what replaced our version instead of deleting the entry, so the
-history of what we carried and why stays reconstructable.
+divergence, newest last. When upstream ships an equivalent, the entry file is
+removed and the divergence moves to the upstreamed table below, so the record
+of what we carried, why, and what replaced it stays reconstructable. Numbers
+are never reused.
 
 ## Writing an entry
 
@@ -29,10 +30,18 @@ Each entry uses these sections:
 
 ## Ledger
 
-| #    | Divergence                                                                                            | PR                                                 | Status |
-| ---- | ----------------------------------------------------------------------------------------------------- | -------------------------------------------------- | ------ |
-| 0001 | [File explorer mention actions and zoom-aware context menus](./0001-file-explorer-mention-actions.md) | [#1](https://github.com/TrogonStack/t3code/pull/1) | active |
-| 0002 | [Draft hero landing on the index route](./0002-draft-hero-landing.md)                                 | [#2](https://github.com/TrogonStack/t3code/pull/2) | active |
-| 0003 | [Native subagent threads for Claude orchestrators](./0003-native-subagent-threads.md)                 | [#3](https://github.com/TrogonStack/t3code/pull/3) | active |
-| 0004 | [Drag files from the explorer into the chat](./0004-file-tree-drag-to-chat.md)                        | [#4](https://github.com/TrogonStack/t3code/pull/4) | active |
-| 0005 | [Selection highlight over composer chips](./0005-composer-chip-selection-highlight.md)                | [#5](https://github.com/TrogonStack/t3code/pull/5) | active |
+| #    | Divergence                                                                            | PR                                                 | Status |
+| ---- | ------------------------------------------------------------------------------------- | -------------------------------------------------- | ------ |
+| 0003 | [Native subagent threads for Claude orchestrators](./0003-native-subagent-threads.md) | [#3](https://github.com/TrogonStack/t3code/pull/3) | active |
+
+## Upstreamed
+
+Divergences upstream has since merged. Our copies were dropped in favor of
+upstream's versions during sync, and the entry files were removed.
+
+| #    | Divergence                                                 | PR                                                 | Upstream PR                                                     |
+| ---- | ---------------------------------------------------------- | -------------------------------------------------- | --------------------------------------------------------------- |
+| 0001 | File explorer mention actions and zoom-aware context menus | [#1](https://github.com/TrogonStack/t3code/pull/1) | [pingdotgg#4054](https://github.com/pingdotgg/t3code/pull/4054) |
+| 0002 | Draft hero landing on the index route                      | [#2](https://github.com/TrogonStack/t3code/pull/2) | [pingdotgg#4055](https://github.com/pingdotgg/t3code/pull/4055) |
+| 0004 | Drag files from the explorer into the chat                 | [#4](https://github.com/TrogonStack/t3code/pull/4) | [pingdotgg#4140](https://github.com/pingdotgg/t3code/pull/4140) |
+| 0005 | Selection highlight over composer chips                    | [#5](https://github.com/TrogonStack/t3code/pull/5) | [pingdotgg#4139](https://github.com/pingdotgg/t3code/pull/4139) |