[Suggestion] Click a pasted block in the composer to view & edit its full contents

提交前确认 · Pre-submission checklist

• 我已搜索过现有 issue，确认这不是重复 / I searched existing issues and confirmed this isn't a duplicate.
• 我已阅读 CONTRIBUTING.md / I've read CONTRIBUTING.md.

使用场景 · Context

When pasting content into the ZCode chat composer, there is currently no easy way to review the full contents of a paste before sending it. This matters because:

• Pasted text can be long (logs, stack traces, multi-line code blocks) and hard to verify inline.
• In some cases pasted text isn't reliably visible/editable inline in the composer today (see related bug #207), so a dedicated viewer would let users confirm exactly what will be sent.

建议方案 · Proposal

Add a "click to view" interaction on pasted content in the composer. Clicking a pasted block/chip opens a lightweight viewer/editor that shows the full pasted text and lets the user:

• Read the entire content (with wrapping and scroll).
• Edit it before sending (fix typos, trim, redact secrets).
• Optionally copy it back or remove it.

Suggested UX: a small "pasted (N lines)" affordance in the composer that opens a modal or inline expander on click. A keyboard shortcut (e.g. activating the block, or Shift+Enter on it) could also trigger it.

预期价值 · Value

• Confidence before send: users can verify exactly what's being sent to the model, reducing mistakes and accidental leaks of large or sensitive content.
• Accessibility of pasted data: works around cases where pasted text isn't visible inline in the composer (#207).
• Peer parity: Codex / Claude Code–style workflows benefit from explicit paste inspection; this complements the existing interaction settings (e.g. zcodeInteractionBehavior: queue).

相关 · Related

• Related to #207 (Windows: pasted text present but invisible/uneditable in composer).

Start by reviewing the pasted-content behavior described in related issue #207 and the existing composer interaction setting zcodeInteractionBehavior: queue. Define the viewer/editor flow, including reading, editing, copying, removing, scrolling, and any keyboard activation; done means pasted blocks can be opened, inspected, edited, and safely sent or removed.