[Session] Resilient pointer storage schema + TTL

[OneStepAt4time]

Problem: continuation metadata/pointer storage lacks explicit resiliency schema and TTL lifecycle. Scope: pointer schema validation, TTL-based cleanup policy, backward-compatible read path, tests for stale/invalid pointers. Ref: docs/plans/aegis-claude-code-technical-backlog.md (B7).

[OneStepAt4time]

PM delegation update (Wave 3)

Status: in-progress
Execution stream: S10
Backlog mapping: B7

Scope

• Add resilient pointer schema + validation.
• Add TTL lifecycle and stale pointer cleanup.
• Keep backward-compatible read path.

Branch

• fix/900-resilient-pointer-storage-ttl

Deliverables

1. Pointer schema module
2. Validated read/write flow
3. Startup + interval eviction
4. Compat + stale/invalid tests

Acceptance

• Pointer reuse only after validation.
• Expired pointers evicted deterministically.
• Legacy metadata path remains functional.

Quality gates

• npx tsc --noEmit
• npm run build
• npm test

Delegation packet: d:/aegis/.tmp/issue-updates/900.md

[OneStepAt4time]

PM update: stream S10 opened in parallel with dedicated worktree wt-900 and branch ix/900-resilient-pointer-storage-ttl.\n\nExecution policy: #900 starts coding immediately after #660 lands, unless blocker arises.

[OneStepAt4time]

PM monitor cycle update:\n- Upstream related wave items merged (#894/#899).\n- #900 remains queued behind #660 per execution order; stream infrastructure already ready in wt-900.