## Summary
The stage-24 plan correctly rejects a permanent master identity and preserves default-off, TTL-bound diagnostics, strict production role separation, and human-only live Telegram/manual P2-P6/deployment. It is nevertheless BLOCK / REQUEST CHANGES: the proposed shared-user diagnostic registry cannot load through the current strict validators, and an existing trainer private-DM route bypasses the stated three-destination isolation.

## Claims
- The RALPLAN index records the supplied planner artifact at stage 24 with SHA-256 `ef53cd64f24670de26f2408eaef1bc6f0ce132e4b371e68306e9eef9af3c1965`.
- `customer_coaching.py:277-359` rejects shared owner/customer/trainer Telegram keys, and `customer_admin.py:1500-1510` always loads that ordinary registry at runtime.
- `telegram.py:4565-4678,8739-8773` and `nutrition_coaching.py:863-1010` expose trainer workflow in a private DM keyed only by trainer user ID.
- `GateDPreflightReceipt` has a closed v1 schema/key contract (`customer_admin.py:4203-4399`); `profile_authority_lock` serializes but does not authorize (`:126-158`).

## Analysis
### Spec compliance
The session, capability pins, restart fail-closed rule, production/diagnostic non-interoperability, synthetic replay, promotion exclusion, and no-live-operation boundary meet the stated objective in principle. The plan also correctly keeps Topic-59 first-match and existing at-most-once/unknown behavior.

Two current boundaries make the implementation slices insufficient. The ordinary Pydantic registry rejects the very same-user topology diagnostic mode needs before preflight or gateway isolation can run. Relaxing those validators globally, or using a durable config boolean, would turn the proposed TTL session into a permanent bypass. Separately, the existing private trainer-DM bridge recognizes `(user_id == chat_id, topic=0)` before normal role routing; shared diagnostic identity makes it an extra unpinned role ingress, not one of the three declared destinations.

The strongest contrary approach is a single registry parser with `diagnostic=true`. Reject it: a persisted flag or tolerant default parser lets ordinary lifecycle callers silently consume shared identities. Use a distinct typed diagnostic loader/context that validates the active revalidated session under the authority lock, keeps the ordinary loader strict, and is the only path allowed to construct shared-user runtime routes. Disable the legacy private trainer-DM bridge in diagnostics (recommended); binding it as an explicit fourth session-pinned destination is viable only if the contract and all ingress tests expand accordingly.

The preflight and snapshot proposals are directionally sound but need compatibility/authentication precision. Preserve the existing ordinary v1 receipt and return a versioned diagnostic result/union rather than widening its closed field maps. A caller-provided `requested_by` plus a lock is not authorization; export must require a freshly validated mode-bound owner/session capability or a named authenticated local-only boundary.

## Root Cause
The plan models diagnostic identity sharing as a preflight/capability exception, whereas current role separation is enforced earlier by the registry schema/runtime loader and additionally widened by a user-ID-only trainer-DM ingress. Those source boundaries must be made explicitly session-scoped; otherwise execution either fails closed permanently or weakens production validation.

## Findings
1. **HIGH (blocker) — `customer_coaching.py:277-359`; reported P1.** Add `customer_coaching.py`, all runtime/activation loader callsites, and dedicated tests to the slice. Keep ordinary parsing strict; use a session-scoped diagnostic loader/context that verifies the exact same canonical user plus three distinct destinations before constructing routes.
2. **HIGH (blocker) — `telegram.py:4565-4678`; reported P1.** Diagnostic mode must disable the private trainer-DM bridge or bind it to an explicit session-pinned destination/capability. Test private-DM text, callbacks, and active bindings as denied/provider-zero in the three-destination design.
3. **MEDIUM (follow-up before implementation) — `customer_admin.py:4203-4399`; reported P2.** Version the diagnostic preflight result and preserve the ordinary v1 receipt serialization and callers unchanged.
4. **MEDIUM (follow-up before implementation) — `customer_admin.py:126-158`; reported P2.** Authenticate snapshot export through a fresh owner/session capability; do not treat `requested_by` or the authority lock as an authorization decision.

## Recommendations
1. Revise the binding contract and file list before coding: ordinary `load_runtime_customer_registry` remains strict, while an explicitly typed diagnostic loader is admitted only after live session revalidation under `profile_authority_lock`; cover activation, reload, restart, expiry, malformed rows, and ordinary-loader rejection.
2. Explicitly remove/deny trainer private-DM routing in diagnostic mode and add it to all-update-kind negative coverage alongside production customer, production route, test-bot, stale callback, and provider-zero assertions.
3. Define `GateDPreflightOptions` and a tagged/versioned ordinary-vs-diagnostic receipt API; preserve v1 ordinary serialization and test both paths.
4. Define snapshot export's authenticated caller/capability, stale/revoked behavior, no-output guarantee, and opaque audit reference. Keep promotion rooted in fixed canonical repository/schema/config allowlists with containment checks; it remains a human-approved manifest, never a deployment executor.

## Architectural Status
BLOCK

## Code Review Recommendation
REQUEST CHANGES

## Tradeoffs
- **Session-scoped diagnostic loader (recommended):** preserves the default strict registry and gives restart/expiry one fail-closed admission point; requires explicit loader propagation.
- **Persistent diagnostic registry/config flag:** less code initially, but creates a reusable master bypass; reject.
- **Disable trainer private DM in diagnostics (recommended):** keeps exactly three declared destinations; diagnostic trainer UX must use its topic.
- **Add private DM as a fourth role destination:** reusable legacy UX, but expands attack surface and session/route verification materially.

Verification was intentionally not run: this was a read-only plan/code review. Live Telegram, account/token work, manual P2-P6, and deployment remain human-only.