feat(session-ui): group adjacent reads into one row - #52207

Adjacent reads now render as one comma-separated row: Read index.tsx, main.ts, rpc.ts. Thoughts, shells, and other tools still split the runs, so the order stays chronological.

• The grouping is automatic. It works inside a Used group, and also when tools render outside one (the everything preset). It has no timeline detail setting.
• Each file keeps its details (connection.ts limit=120) and uses the same title, filename, and arg colors as the single-read rows.
• A long row truncates with an ellipsis. Only a truncated row can be clicked: click, Enter, or Space wraps it in place to show every file. The open state is persisted like other tool rows.
• Image reads, reads that loaded instruction files, and failed reads keep their own rows.

flowchart LR
  A[read a.ts] --> G1["Read a.ts, b.ts limit=120"]
  B[read b.ts limit=120] --> G1
  T[thought] --> T1[Thought 4s]
  C[read c.ts] --> G2["Read c.ts"]
  I[read logo.png] --> I1["Read logo.png (own row, image preview)"]

	Before	After
Inside Used
Without a Used group

Narrow width, with one row expanded and one row hovered:

Fixture: OpenCode/Work/Read group (packages/session-ui/src/tools/read-group.stories.tsx) reproduces the reported 65-tool turn. It has a width control.