Merge origin/master into experiment/in-process-assistant

Resolve conflicts in the workspace assistant integration:

- DynamicFormItemComponent: keep HEAD's compact model selector and
  `disabled` field support while adopting master's `sortModelsByCatalog`
  ordering and `MODEL_SELECT_TRIGGER_CLASS`.
- i18n (en-US, ja-JP, zh-Hans): keep both the `assistant` namespace from
  HEAD and master's `sidebarGuide` / `pipelineMigration` additions.

Add 0030_merge_assistant to join the assistant conversations branch with
the released chain so the migration graph converges on a single head.
Rename it from 0030_merge_assistant_conversations to stay within the 32
character revision limit enforced by test_migrations.

Also add assistant button docking (long-press drag, edge collapse to a
short blue rail, hover restore) with pure helpers in assistant-dock.ts
and unit coverage, plus auto-collapse for finished tool result cards.

src/langbot/pkg/persistence/alembic/versions/0030_merge_assistant.py

@@ -1,14 +1,16 @@
 """Join the workspace assistant conversations branch with the released chain.
 
-Revision ID: 0030_merge_assistant_conversations
+Revision ID: 0030_merge_assistant
 Revises: 0029_merge_rag_identity, 0025_assistant_conversations
 
 The assistant conversation tables ship independently of the released schema
 chain. Both parents are already published, so this revision only joins the
-graph; Alembic applies the missing branch before this no-op merge.
+graph; Alembic applies the missing branch before this no-op merge. The
+identifier is kept within the 32 character limit enforced by the migration
+graph test.
 """
 
-revision = '0030_merge_assistant_conversations'
+revision = '0030_merge_assistant'
 down_revision = ('0029_merge_rag_identity', '0025_assistant_conversations')
 branch_labels = None
 depends_on = None