docs: insert Phase 70.1 for rotation read-plane durability

[FSM1]

Insert Phase 70.1 — Rotation Read-Plane Durability and Deep Crash-Resume Soundness

Planning-only change (.planning/ docs). Inserts a decimal phase between 70 and 71 to close the rotation read-plane debt disclosed at Phase 70 ship (PR #596 review) — it doesn't fit Phase 71 (API/share-invite), 72 (write plane), or 73 (web), and mirrors the 68.1/68.2 decimal-phase precedent.

Scope (3 workstreams)

1. Depth>=2 crash-resume soundness — the dirty-frontier consumption path is depth-1-only and reuses a stale child key at dirty edges. Phase 70's SC#2/SC#3 are proven only for depth-1/childless-root as shipped (the e2e gate used a childless root by design). From 2026-07-08-rotation-crash-resume-depth2-soundness-gap.md.
2. Floor-store durability — surface write-failures through HighWaterStore::put/bump_floor (CodeRabbit T4) + cross-store bump atomicity (hardening item 1).
3. Reconcile gate — feed the freshly-resolved generation, not the cached one (hardening item 5).

Gate: a new depth-2/3 mid-walk-crash case in rotation-crash-safety.test.ts.

Bookkeeping

• Depth-gap todo retargeted (resolves_phase: 70.1).
• rotation-hardening-followups todo annotated — items 1 + 5 folded into 70.1; items 2/3/4/6 already closed by Phase 70. Left without an auto-close marker (only 2 of 6 items remain).
• STATE: total_phases 15 -> 16, current position -> 70.1. The derived progress counters (completed/percent) were already stale on main from the Phase 70 merge and will reconcile on the next GSD state write.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Documentation
  • Added a new roadmap entry outlining the next planned reliability work.
  • Updated project planning status to reflect the new focus and progress.
• Chores
  • Added and updated planning notes to track follow-up items and upcoming work.
  • Preserved the new planning directory in version control.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 5ea02b13-c798-42e9-af48-0196e5ad0e68

📥 Commits

Reviewing files that changed from the base of the PR and between faa781e and 135525c.

📒 Files selected for processing (5)

• .planning/ROADMAP.md
• .planning/STATE.md
• .planning/phases/70.1-rotation-read-plane-durability-and-deep-crash-resume-soundne/.gitkeep
• .planning/todos/pending/2026-07-02-rotation-hardening-followups-from-pr-review.md
• .planning/todos/pending/2026-07-08-rotation-crash-resume-depth2-soundness-gap.md

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Walkthrough

This PR adds planning documentation for a new Phase 70.1, addressing rotation read-plane durability and deep crash-resume soundness gaps found in PR #596 review feedback. It updates the roadmap, project state, adds a phase directory placeholder, and retargets two pending todo files to reference the new phase.

Changes

Planning documentation updates

Layer / File(s)	Summary
Define Phase 70.1 in roadmap and phase directory .planning/ROADMAP.md, .planning/phases/70.1-rotation-read-plane-durability-and-deep-crash-resume-soundne/.gitkeep	Adds a new roadmap section detailing Phase 70.1 goals, dependencies on Phase 70, and success criteria (depth≥2 crash resume, dirty-frontier ordering, floor-store write-failure atomicity, reconciliation gating, new sdk-e2e test); creates the phase directory placeholder.
Point project state at Phase 70.1 .planning/STATE.md	Updates current phase metadata and "Current focus" section from Phase 71 to Phase 70.1, adjusting status, dependency notes, and timestamps.
Retarget pending todos to Phase 70.1 .planning/todos/pending/2026-07-02-rotation-hardening-followups-from-pr-review.md, .planning/todos/pending/2026-07-08-rotation-crash-resume-depth2-soundness-gap.md	Adds retargeting instructions folding open items into Phase 70.1 and adds a resolves_phase: "70.1" field to the crash-resume todo.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• FSM1/cipher-box#595: Both PRs update .planning/ROADMAP.md to define rotation/crash-resume soundness phases, with this PR adding the specific Phase 70.1 section.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch docs/phase-70.1-rotation-read-plane-durability

Warning

Tools execution failed with the following error:

Failed to run tools: 13 INTERNAL: Received RST_STREAM with code 2 (Internal server error)

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[github-actions]

Release Preview

No version bumps detected. All changes are in unversioned paths or use exempt commit types.

[greptile-apps]

Greptile Summary

This PR inserts a new planning phase for rotation read-plane durability.

• Adds Phase 70.1 to the roadmap with goals and success criteria.
• Updates planning state to make Phase 70.1 the current phase.
• Creates the placeholder phase directory.
• Retargets the relevant pending rotation follow-up todos.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.
• The planning files are consistent with the new Phase 70.1 insertion.
• Decimal phase identifiers already appear in the planning structure.

Important Files Changed

Filename	Overview
.planning/ROADMAP.md	Adds Phase 70.1 with its dependency, source todos, context, and success criteria.
.planning/STATE.md	Moves the current planning position from Phase 71 to Phase 70.1 and updates phase counts.
.planning/phases/70.1-rotation-read-plane-durability-and-deep-crash-resume-soundne/.gitkeep	Creates the placeholder directory for the new Phase 70.1 work area.
.planning/todos/pending/2026-07-02-rotation-hardening-followups-from-pr-review.md	Documents that only the remaining hardening follow-ups are folded into Phase 70.1.
.planning/todos/pending/2026-07-08-rotation-crash-resume-depth2-soundness-gap.md	Adds Phase 70.1 as the resolving phase for the crash-resume depth gap todo.

_{Reviews (1): Last reviewed commit: "docs(roadmap): insert Phase 70.1 for rot..." | Re-trigger Greptile}