# PR-34 Tile Bank Diagnostics and Validation Hardening

Domain Owner: `docs/packer`
Cross-Domain Impact: `docs/studio`

## Briefing

The tile-bank decision closed the structural blockers and warnings that must exist before pack emission.

Those diagnostics belong in the walker/materialization path so they surface during validation and are naturally rerun by `packWorkspace(...)` when a fresh frozen snapshot is created.

This PR isolates that diagnostic work from payload emission.

## Objective

Add the accepted tile-bank diagnostics to the packer walk/materialization path and make validation consume them consistently.

## Dependencies

- [`../decisions/Tile Bank Packing Materialization Decision.md`](../decisions/Tile%20Bank%20Packing%20Materialization%20Decision.md)
- [`../decisions/Pack Wizard Pack Execution Semantics Decision.md`](../decisions/Pack%20Wizard%20Pack%20Execution%20Semantics%20Decision.md)
- `PR-33` for normative spec propagation

## Scope

- add tile-bank structural blocking diagnostics
- add tile-bank warning diagnostics for fragile indices
- ensure those diagnostics live in the walker/materialization path
- ensure validation consumes them without special late pack-only logic

## Non-Goals

- no full payload emission yet
- no staging/promote pipeline yet
- no shipper behavior
- no future multi-tile-per-artifact support

## Method

1. Add blocking diagnostics for:
   - duplicate `artifacts[*].index`
   - gaps in normalized artifact indices
   - fixed-sheet capacity overflow
   - banks without declared palettes
   - palette declaration count above `64`
   - malformed palette declarations
   - missing or invalid required tile-bank metadata
   - failures to normalize artifacts into deterministic tile candidates
2. Add `WARNING` diagnostics for fragile tile indices across the full declared bank palette set.
3. Ensure diagnostics are attached at file/asset walk time so:
   - `GetAssetDetails`
   - `ValidatePackWorkspace`
   - future pack rerun gate
   all see the same structural findings.
4. Add tests that distinguish blocking failures from advisory warnings.

## Acceptance Criteria

- validation returns blocked tile-bank assets when any accepted blocker exists
- fragile-index findings are visible but do not block by themselves
- no tile-bank structural problem is discovered only during final byte emission
- the same diagnostic vocabulary is visible in details and validation paths

## Validation

- targeted service and walker tests
- validation-flow regression tests
- asset-details regression tests for warning and blocking surfaces

## Affected Artifacts

- `prometeu-packer-v1` tile-bank walker/materialization code
- `prometeu-packer-v1` validation/query services
- related tests under `prometeu-packer-v1/src/test`