[feat] Multi-surface echo shapers — tweet + recap generators

[kody-w]

Description

Implement L1 and L2 echo shapers that produce social media content and recap summaries from frame history.

Shapers

1. Tweet shaper — generates a 280-char tweet from frame data
2. Recap shaper — generates a paragraph summary of the last N frames
3. Changelog shaper — generates patch-notes-style diff between frames

Tasks

• Register shapers in EchoEngine
• Add 'Generate Tweet' button in bridge
• Add 'Session Recap' tab in bridge
• Copy-to-clipboard for generated content
• Include agent names, economy state, combat events in output

Echo Level

L1-L2 — social surface rendering from raw frame data.