docs(roadmap): mark decision-to-code-proximity Achieved [roadmap:decision-to-code-proximity]

[tcballard]

Summary

Closing hygiene for the now-complete decision-to-code-proximity programme (epic #273, all three initiatives merged via #284/#285/#286): move the roadmap to its terminal lifecycle status, correct a missed requirement status, and record the user-visible changes in the changelog.

Changes:

• Roadmap → Achieved (ADR-061) with a delivery summary of the three initiatives.
• rac-path-decisions-lookup → Accepted — it shipped in decision-to-code-proximity: path→decisions lookup — CLI subcommand plus additive find_decisions path argument #275 but was left Proposed.
• CHANGELOG Unreleased section capturing the programme's user-visible surface.

Roadmap / ADR Trace

• rac/roadmaps/decision-to-code-proximity.md — the roadmap being closed out
• adr-061 — Roadmaps Carry an "Achieved" Terminal Lifecycle Status
• adr-076 — CalVer releases: the changelog entry is renamed to the release heading when the next release is cut

Scope

Included

• Roadmap Status: Planned → Achieved, prose updated to a delivery summary (which initiative shipped what, over which surfaces).
• rac-path-decisions-lookup Status: Proposed → Accepted, with a delivery note (the rac decisions-for CLI and the find_decisions MCP path argument).
• A CHANGELOG ## Unreleased section: the ## Applies To code-scope declaration and its validation finding, rac decisions-for, the additive find_decisions path argument, and the Explorer /decisions-for command — framed by user impact.

Excluded

• No code or behaviour changes; corpus and changelog only.
• No release cut — the Unreleased heading is renamed to a CalVer version when the maintainer publishes (per verify_release, ADR-076).

Product / Architecture Decisions

• Documentation trail, for the record. The programme's what/why already lives in the corpus (roadmap, the two requirements, the code-scope-consumption design, the four dogfooded evidence ADRs) and its usage in the docs (docs/relationships.md code-scope section, docs/cli.md decisions-for). The one gap was the changelog — added here as Unreleased so a user scanning release notes sees the capability, consistent with the file's stated "spirit of Keep a Changelog."
• Achieved, not closed-and-gone. Per ADR-061 an achieved roadmap is a live terminal record — still valid to reference — so no inbound reference to it becomes a retired-target finding (rac relationships --validate stays clean).

Verification

Ran

• rac validate rac/ → PASS — 373 valid, 0 invalid (roadmap now Achieved, requirement now Accepted).
• rac relationships rac/ --validate → exit 0; rac review rac/ → no priority 1–2 findings.
• pytest tests/test_release_version.py → 25 passed (the Unreleased heading is inert to changelog_has_entry, which matches a ## <version> heading; the real-file check runs only at release with a version).

Review Path

1. rac/roadmaps/decision-to-code-proximity.md — the status flip and delivery summary.
2. rac/requirements/rac-path-decisions-lookup.md — the missed Accepted flip.
3. CHANGELOG.md — the Unreleased section.

Notes For Reviewer

• Rename ## Unreleased to the CalVer version heading when the next release is cut; verify_release will then find the entry.
• Post-merge: no further bookkeeping — epic Epic: decision-to-code-proximity — decisions at the point of edit #273 and all sub-issues are already closed.

Implementation Process

Implemented with AI assistance; the status flip was requested and the changelog capture confirmed by the maintainer.