v0.2.19

chore: remove deleted nagi repository from policy (#92)

## Summary

- Remove the deleted `civitaspo/nagi` repository from deployment policy
and fixtures.
- Update the caller inventory to eight and use the configured
`herdr-linear-agent` repository in distribution tests.
- Apply Rust formatting and reserve fresh runtime version `0.2.19`
consistently in Cargo.toml and the lockfile package entry.

## Validation

Reviewed signed head: `8a9a498aed9f9716cb57874b912c5d7f32939568`.

- Format check, locked full Rust tests (224 passed; 2 ignored), and
clippy passed with Rust 1.99.0.
- [Exact-head Actions CI and required status-check
passed](https://github.com/civitaspo/securefix-server/actions/runs/38857572644).
- Independent automated [PASS+NOTES
review](https://github.com/civitaspo/securefix-server/pull/92#issuecomment-6209018193):
registry/policy tests and actual CLI policy validation passed.
Same-model independent review.
- Stable patch ID: `1d143b8463798b15be9afe953c56333ac5aeb3a4` against
base `9b8d70a`.

## Recovery status

Not merged or published. Approve Request and Policy Check cannot load
the exact-main runtime: current main declares `0.2.18`, but the
immutable `v0.2.18` release belongs to a previous SHA. The fresh version
at this PR's head cannot repair that base loader.

A recovery proposal used only for PR92 is awaiting explicit owner
authorization: temporarily add only the owner User's PR-merge bypass to
the two blocking rulesets, merge this reviewed exact head, and
immediately remove the added actor with a concurrent-change check.
GitHub scopes this bypass to the actor and rulesets, not the PR number;
no other merge is allowed during that window. Default-branch protections
remain intact. No protection mutation has occurred. Normal
protected-main publication of `0.2.19` would follow, restoring the
ordinary approval/merge flow for maintenance PR #93 (`0.2.20`).
Publication and all eight caller distribution jobs remain unverified.