Performance: Stream review results via SSE instead of polling

[tailorgunjan93]

Performance: Replace Polling with Streaming (SSE)

Problem

The current review flow uses ReviewPoll() — a polling loop that repeatedly
hits the LiveReview backend until results are ready. This creates:

• Perceived latency (user stares at a spinner)
• Unnecessary HTTP round-trips
• Delayed inline comments (all arrive at once)

Proposed Solution

Switch to Server-Sent Events (SSE) for streaming inline comments
as the AI generates them — similar to how ChatGPT streams responses.

User Experience Difference

Current:  [spinner 8 seconds] → all 5 comments appear at once
Streaming: comment 1 appears → comment 2 → comment 3 → (feels instant)

Implementation Approach

Backend — LiveReview API adds an SSE endpoint:

GET /api/v1/diff-review/stream?review_id=xyz
Content-Type: text/event-stream

data: {"line": 12, "file": "main.go", "comment": "Possible nil dereference"}
data: {"line": 34, "file": "auth.go", "comment": "Leaked credential pattern"}
data: {"status": "complete", "coverage": 85}

CLI — Replace ReviewPoll() loop with SSE client:

// net/http SSE reader in Go is straightforward
resp, _ := http.Get(streamURL)
scanner := bufio.NewScanner(resp.Body)
for scanner.Scan() {
    line := scanner.Text()
    // parse and forward to UI
}

Browser UI — Already JS-based, EventSource API is native:

const es = new EventSource(streamURL);
es.onmessage = (e) => renderComment(JSON.parse(e.data));

Benefits

• Feels 3-5x faster to the user (same total time, better perceived speed)
• Reduces server load (one connection vs. N polls)
• Comments render progressively — user can start reading while AI continues