feat: implemented v0.3.2 verified changepacks

[Shiva936]

• Imported-pack lifecycle is now fully reachable: quarantined imports are locally re-verified from embedded content, approved/rejected, and saved with conflict-checked content application (checkpointed, promoted out of quarantine); origin trust marks are stripped at import.
• .draftpack format 2 embeds the content-addressed objects a patch references; import verifies each object against its content address and rejects wrong-schema receipts (fail closed).
• Policy layer is enforced: field-level resolution (project > global > safe default) governs the save gate (approval, critical-risk block, high-risk approval, workspace re-verification) and intent-based full/fuzz verification escalation; malformed policy files fail closed.
• Save gate reads the canonical risk report; unresolved critical risk (or a missing report) blocks save under the default policy.
• draft rollback rcp_ resolves canonical signed receipts (verified, rollback-eligible event types) in addition to legacy receipts.
• draft verify <pck_id> also records the legacy verification receipt for legacy packs so the save gate is consistent across both verify forms.
• Risk reports persist the ML-ready feature vector plus real dependency counts and candidate rollback-rate signals.
• draft doctor --global lists adapter statuses; acp-comm is explicitly experimental. LSIF packs_touching_symbols now shortlists pack_depends.
• Docs, CHANGELOG, and release notes updated to match implementation; new tests (lifecycle e2e, tamper/conflict fail-closed, policy gates, canonical rollback, receipt schema, adapter status).