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## Summary

<!-- One or two sentences. What changed and why. -->

## Changes

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Bulleted list of substantive changes. Keep it tight; the diff is the source of
truth, this is the index.
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-
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## CHANGELOG entry

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### Added

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### Changed

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### Deprecated

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### Removed

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### Fixed

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### Security

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## Stability tier impact

<!--
Check one. Definitions in docs/api/versioning.md.

- [ ] No external surface touched (internal refactor / docs / tests / CI).
- [ ] Additive change to a `stable` surface (new optional param, new field, new event type).
- [ ] Breaking change to a `stable` surface (requires major bump — block until release planning is in scope).
- [ ] Change to an `experimental` surface (note in release notes).
- [ ] Change to an `internal` surface (no contract impact).
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## Substrate contract impact (Substrate 3.0)

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If this PR touches any of these, link to the relevant docs section that needs
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- PaneMetadata wire shape, mergeMode, version semantics → docs/PROTOCOL.md §1
- EventBus envelope, cursor semantics, bootId → docs/PROTOCOL.md §2, §3
- Permission enforcement points → docs/PROTOCOL.md §4
- Named Pipe security → docs/PROTOCOL.md §5
- New RPC method / event type → docs/api/inventory.md + docs/api/stability.md

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## Test plan

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- Unit tests added / updated: which paths.
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## Related issues / PRs

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## Reviewer checklist

- [ ] CHANGELOG entry above is filled in or explicitly marked n/a.
- [ ] Stability tier impact is correctly classified.
- [ ] Substrate contract docs (PROTOCOL.md, inventory.md, stability.md) updated if the surface changed.
- [ ] Tests cover the new behavior and the regression case (if a bug fix).
- [ ] No accidental commit of secrets, tokens, `.env`, or unrelated large binaries.
