[mblua]

Reject repeated decoded JSON member paths before consuming AgentsCommander configuration, returning the physical file and cause while preserving its bytes and native syntax/IO policy. Add checked configuration providers and read-only startup session selection; consumer migration continues in subsequent phases of #2992.

Validated locally on Windows at bf18098: all 11 admission tests and 9 layering checks passed, along with all-targets, formatting, the existing Clippy/cognitive gate, module arcs and complete SCC comparison. Rust, architecture and UI reviewers approved code and proof for this exact commit, including the full change since the previous review. Temporary function-level dead-code annotations retain prepared helpers until their planned consumer migrations. The PR changes ten owned paths; eleven historical upstream imports match current main.

Approved specification: master v29 / P52 v5, Full R23. Proof SHA256: 2B71FCBEB469A0CD42802CEF4D80C765F4D3A687C8B253EE2247EE147EB226CF. Three-review receipt SHA256: C00F6A6F7A016409EA36AF3E9512ABA1585C89853AA5345325F9ED7FB0345749. Main was fetched and remains f183d6e, already included in this commit. Fresh full CI is required before merge.

Closes #3146

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[mblua]

Heads-up: the required checks on main changed (#3184, PR #3185).

The main ruleset now requires these checks instead of the old names:

• rust-regression is now rust-regression-windows
• windows-release-cli-smoke is now release-cli-smoke-windows
• new: issue-1850-release-windows, issue-1850-release-linux, issue-1850-release-macos and rust-slow-test-windows

This branch still runs the old workflow, so those checks never report here and the PR cannot merge as it is.

What to do when this PR is ready to land: wait until PR #3185 is merged, then bring this branch up to date with main (the ruleset already requires that). The new workflow comes with it and reports the new check names. Resolve any conflict in .github/workflows/pr-regression-gates.yml in favour of main.

[mblua]

Superseded by the replanning of #3146 under epic #2992 on branch refactor/3146-settings-owner-current-structure, based on current main 56a7d00e433c6b0b1b5fa0c5c0a6c2d328522e13.

The user authorized this restart through room-37 (P50 option 1, 2026-10-27). The original changes target an obsolete file structure and will not be ported mechanically. The old branch refactor/3146-settings-owner-p52-configuration-admission and commit 9cd29994473127b6953f33fca6c145ccb413e4c8 are preserved as reference. No merge or functional completion is claimed. Fresh plan consensus, reservations and human approval remain required before implementation.