feat(synthesis): require curated theme submissions

[gregkonush]

Summary

• Requires strict synthesized-theme submissions for Synthesis MCP/API items.
• Stores one curated item per theme with source mappings, fact checks, app-owned attachments, and generated infographic attachments.
• Removes raw-detail UI duplication and renders synthesized detail, source chips, fact checks, score/confidence, and attachments.
• Pins the Synthesis GitOps image tag to the built strict-contract image xcurate-strict-20260526001830.

Related Issues

None

Testing

• bun run --filter synthesis test
• bun run --filter synthesis lint
• bun run build:synthesis
• python /Users/gregkonush/.codex/skills/.system/skill-creator/scripts/quick_validate.py /Users/gregkonush/.codex/skills/xcurate
• Local MCP smoke against http://localhost:4637/mcp: strict synthesized-theme submit succeeded, old top-level originalUrl/observedText/summary submit failed with Invalid synthesis_submit_item input.
• Built and pushed registry.ide-newton.ts.net/lab/synthesis:xcurate-strict-20260526001830; verified registry digest sha256:1ff6b0d075e62c7d7f91df820e63bf0a59f0468a25d6441ab37546cc64c0f862.

Screenshots (if applicable)

N/A - no visual screenshot required; UI behavior is covered by local feed/detail smoke and tests.

Breaking Changes

Synthesis submit callers must now send the strict synthesized-theme contract: title, synthesis, takeaways, whyValuable, sourcePosts, dedupeKey, score, and confidence. Top-level originalUrl, observedText, summary, evidence, and mediaUrls are rejected.

Checklist

• Testing section documents the exact validation performed (or N/A with justification).
• Screenshots and Breaking Changes sections are handled appropriately (removed or filled in).
• Documentation, release notes, and follow-ups are updated or tracked.