docs(ecosystem): add opencode-mempalace-persistence to plugins table

[geco]

Issue for this PR

Supersedes #30595 (closed by automated cleanup) and #30540 (closed by compliance bot). Follows up on showcase #27752.

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Adds opencode-mempalace-persistence to the ecosystem plugins table. The plugin persists conversations to MemPalace (local vector DB, zero cloud) in real-time. Now at v2.1.0:

• Auto-inject memory — uses experimental.chat.messages.transform to inject identity + relevant MemPalace memories into every prompt. Zero model discipline required.
• AI checkpoints — every 15 messages the model files topics/decisions/quotes via MCP tools; pre-compaction emergency save + synchronous exit save.
• Delta-only sync — only new messages since last sync, exports grouped one wing per project. No duplicates.
• Knowledge Graph + diary — model records structured facts and session journals via MCP tools.
• Mining — mempalace mine --mode convos --extract general (decisions, preferences, milestones, problems). Async, never blocks the UI.

Published on npm as opencode-mempalace-persistence (MIT, fully open source).

How did you verify your code works?

Single-line table addition. Verified the markdown renders correctly in the existing table format. Plugin itself is in daily use (dogfooded, 5.5k+ drawers mined).

Screenshots / recordings

N/A (documentation-only change).

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR