feat(tui): open execute call details dialog on click

[rekram1-node]

Summary

Clicking the execute tool row in the V2 TUI session view now opens a dialog with the program's source and its output. All existing row behavior is unchanged: the child tool-call list, click-to-expand on each child call, the inline error preview, and click-to-toggle on tool-level errors.

Dialog (packages/tui/src/routes/session/dialog-execute.tsx)

• Header with status (Receiving code… / Running / Completed · 2.2s / Failed · 187ms)
• Source is syntax-highlighted with line numbers, shown as written (no reformatting dependency)
• Output: a JSON result is highlighted with the json parser and numbered; its gutter is aligned with the code gutter so both blocks start on the same column. Trailing Warnings: / Logs: sections stay plain text; error output is rendered in the error color
• Code and JSON are not wrapped (indentation stays intact); ←/→ pans long lines. Fits its content up to ~70% of the terminal height, then scrolls (↑/↓, pgup/pgdn, home/end)
• c copies the code, o copies the output
• The part is passed reactively, so a dialog opened while the call is running fills in as output arrives

Refactor

• ExecuteCall, executeCalls, executeCallSummary moved from routes/session/index.tsx to util/tool-display.ts; executeCallSummary is still re-exported from the session route for the existing test.

Screenshots

Testing

• bun run lint and bun typecheck (packages/tui) pass
• bun test test/cli/tui/inline-tool-wrap-snapshot.test.tsx passes (covers executeCallSummary)
• Verified live via bun run dev:live: open via click, child-call expand still works, copy shortcuts, esc, narrow (80 col) and wide (140 col) layouts, success and failed calls, wrapped-code height fitting