[FEATURE]: IDE-native Diff Review & Accept/Reject Workflow for Code Changes Made by opencode #9578

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Problem Statement

Currently, when opencode modifies project code via the CLI, users must manually inspect diffs using terminal-based tools (e.g. git diff). This workflow becomes increasingly difficult to read and review as:

• The number of edited files grows
• Changes are interleaved across multiple directories
• Edits are non-trivial (refactors, multi-line logic changes)

By contrast, most Agentic IDEs (e.g. Cursor, VS Code native agents, Windsurf) provide a first-class review experience, including:

• Inline, line-by-line diff markers inside the IDE editor
• File-level navigation for modified files
• Per-line or per-hunk accept / reject controls

The lack of this capability in a CLI-first workflow significantly reduces readability, reviewability, and trust in agent-generated code.

Proposed Feature

Introduce an IDE-integrated review mode that allows code changes made by opencode to be reviewed inside a running IDE, with native diff and accept/reject semantics.

Core Capabilities

1. Line-by-line diff rendering inside IDE editors

   • Modified lines are visually marked (added / removed / changed)
   • Mirrors the experience of native code agents

2. Review Navigator / Change Explorer

   • Sidebar or panel listing all edited files
   • Click-to-jump navigation between files and hunks

3. Granular Accept / Reject Controls

   • Accept or reject:

     • Individual lines
     • Hunks
     • Entire files

   • Changes are only applied once accepted

4. Multi-IDE Support (initially via extensions or protocol)

   • VS Code
   • Cursor
   • Windsurf
     (Any IDE capable of consuming LSP / extension-based diff APIs)

Why This Matters

• Brings opencode to parity with modern Agentic IDE experiences
• Makes large or critical refactors auditable and safe
• Improves developer trust and adoption in production codebases
• Eliminates the cognitive overhead of reading raw CLI diffs

For users who prefer CLI-driven agents but still rely on IDEs for deep code comprehension, this feature would be a major usability unlock.

Expected Impact

• Better human-in-the-loop workflows
• Reduced accidental regressions
• Faster review cycles
• Wider adoption among professional developers