feat(cli): cross-flavor inline image and video display via MCP and ACP

[heavygee]

Summary

Cross-flavor inline image and video in HAPI web chat (not Cursor IDE composer):

• CLI MCP: display_image and display_video in startHappyServer; stdio bridge forwards both; buildHapiMcpBridge auto-approves both tools.
• Prompts: Shared displayImagePrompt / display_video exports for Claude, Codex, and HAPI_MCP_BRIDGE_PROMPT (Cursor, Gemini, Kimi, OpenCode first-prompt injection).
• ACP: Image content blocks → generated-image agent messages; generated media stored in CLI memory and served via hub GET /api/sessions/:id/generated-images/:imageId (images and video share this route).
• Web: GeneratedImageCard renders <img> (with tiny-image upscale + stable blob fetch) or <video controls> when mimeType is video/*.
• Tooling: hapi-display-image.mjs routes mp4/webm to display_video (absolute paths); loads hapiMcpUrl from per-session GET.

Test plan

• bun typecheck
• CLI: generatedImages.test.ts, buildHapiMcpBridge.test.ts, codexMcpConfig.test.ts, AcpMessageHandler.test.ts, messageConverter.test.ts
• Web: generatedInlineMedia.test.ts
• Manual: display_image PNG and display_video MP4 on Cursor session with hapiMcpUrl; inline cards in HAPI web

Issues

Closes #956

[github-actions]

Findings

• [Major] ACP inline media can be emitted before preceding assistant text. The new image branch flushes reasoning but leaves bufferedText open, while emitGeneratedImageFromAcpContent() emits asynchronously. For a normal ACP sequence like text chunk -> image block -> turn drain, the generated-image message can reach the web UI before the text that came first in the stream. Evidence: cli/src/agent/backends/acp/AcpMessageHandler.ts:559.

Questions

• None.

Summary

• Review mode: initial
• One ordering regression found in the latest diff. Residual risk: media fetch/cache behavior was reviewed statically only.

Testing

• Not run (automation). Suggested coverage: ACP handler test that sends a text agentMessageChunk, then an image agentMessageChunk, then drains, and asserts text precedes generated_image.

[github-actions]

Findings

• [Major] Generated media cards can keep rendering a stale blob after imageId changes.
• [Major] ACP image registration can let later updates render before the image block that preceded them.

Summary
Review mode: initial
Latest PR diff reviewed in full. The main residual risk is around generated media lifecycle/order because the new tests cover happy-path conversion and MIME helpers, but not component prop changes or ACP image blocks followed by later updates.

Testing
Not run (automation)

HAPI Bot

[github-actions]

Findings

• [Major] Await ACP updates that arrive during the late-drain window before emitting turn_complete. cli/src/agent/backends/acp/AcpSdkBackend.ts:429

Summary
Review mode: follow-up after new commits
The previous stale-blob and initial ACP ordering findings are addressed. One ordering gap remains in the follow-up fix: late ACP image/file-backed updates can still be queued during drainLateBuffers() and emitted after turn_complete.

Testing
Not run (automation). Suggested: ACP prompt lifecycle test where a local-path image update arrives during drainLateBuffers() and must appear before turn_complete.

HAPI Bot

[github-actions]

Findings

• [Minor] AVIF files are now routed to display_video, so the helper rejects a supported image format. scripts/tooling/hapi-display-image.mjs:32
  Suggested fix:

  if (head.length >= 12 && head.subarray(4, 8).toString('ascii') === 'ftyp') {
      const brand = head.subarray(8, 12).toString('ascii')
      return brand === 'avif' || brand === 'avis' ? 'display_image' : 'display_video'
  }

Summary
Review mode: follow-up after new commits
One minor issue found in the helper script. The previous ACP ordering finding is addressed by the added post-drainLateBuffers() queue drain.

Testing
Not run (automation). Suggested: add a script/media sniffing test or shared helper coverage for AVIF vs MP4 ftyp routing.

HAPI Bot

[github-actions]

Findings
No issues found.

Summary
Review mode: follow-up after new commits
The follow-up commit addresses the previous AVIF ftyp routing finding. I reviewed the full current diff across MCP/ACP media registration, generated-image RPC serving, web rendering, and helper tooling; no new high-confidence correctness, security, data-loss, or regression findings found. Residual risk: I did not run the full Bun test suite in this automation environment.

Testing
Not run (automation)

HAPI Bot