feat(content-ops): ship reviewed X composer experience seed

[huangruiteng]

Summary

Ship a public, versioned X composer experience seed through the existing content-ops / built-in social_browser_x provider. New agents can discover it through both value-connectors source-map and install-check, without inheriting another session or enabling a memory backend.

The lesson includes the negative result, not only the tempting workaround: a correct composer preview did not survive long-post publication; the published card pointed to the first supporting URL. Body URL order, typing order, and published-card association are distinct. Trying the intended URL first remains an unverified mitigation, not a core rule or guaranteed fix.

Ownership and behavior

• Keep the existing outcome capability and provider; no new capability, extension, memory store, or scheduler.
• Bundle the seed JSON in the wheel with version, content digest, applicability, limitations, and caller-reviewed initialization guidance.
• Reuse Reward Memory's existing scoped_feedback candidate/ingestion boundary and existing Turn Recall surface. No automatic import, provider activation, private-memory sharing, or publication authority.
• The additive default is read-only advisory metadata in the X provider projection. Other connector profiles remain unchanged. Bundled discovery is implemented; live memory initialization and published X card success are not claimed.
• No frontend/Lark companion is needed: this change adds no settings or runtime configuration behavior and is exposed through existing provider discovery/CLI entry points.
• Future-facing pass: reuse the current provider-owned packet and package-resource boundary; defer a generic seed-import framework until there is an active caller requiring it.

Validation

• Focused social-profile + Reward Memory ingestion tests: 14 passed. Covers seed discovery, package digest, non-X parity, absence of writes, reviewed initialization candidate, unverified guard, and rejection of publication authority.
• value-connectors-github-public-probe-smoke.py and content-ops-packet-aggregation-smoke.py.
• Ruff and git diff --check.
• Built wheel and isolated wheel-only import/readback of source-map and install-check seed.
• Candidate-path private-path/credential/internal-link scan clean. No drafts, screenshots, raw trajectories, credentials, or local operating state included.

Full CI remains a remote review gate. No live X post or memory-provider write was used as a test. This PR is uploaded for review, not self-merged.