docs: define engineering evolution and incremental buildout

[TheAmericanMaker]

Summary

• Establish an agent-ready engineering evolution handoff: vision/decisions, sanitized dogfood observations, proposed record contract, and an incremental implementation plan.
• Make in-place changes independent of mandatory library synthesis, with host-owned execution, durable change/attempt identities, evidence freshness, and explicit human authority.
• Update the product roadmap and navigation; preserve the Helix/Traverse discussion as superseded design history rather than competing instructions.
• Link the dependency-tracked implementation issues under Engineering evolution: supervised, evidence-backed local changes #398. This PR documents future work; it does not implement or close those features.

Publication safety

• Only ten Markdown files are included. No raw machine logs, local test archives, credentials, user-home paths, private repository inventories, or provider account configuration are published.
• The historical draft's machine-specific model preference was generalized.
• Staged Git objects were checked for sensitive patterns and relative-link integrity; an independent privacy/claim-scope review approved the candidate.
• Independent plan review found a missing future engineering-state distribution boundary. E02 now explicitly requires Git/template/npm exclusions and synthetic initialization/packed-file inventory tests; re-review approved the correction.

Verification

• npm ci --ignore-scripts
• npm run build — passed
• npm test — 939 passed; zero failed, cancelled, skipped, or todo
• npm audit --omit=dev --audit-level=high — zero vulnerabilities
• git diff --cached --check — passed
• Relative Markdown links and the eleven-task dependency graph checked
• Twelve GitHub issues read back; eleven native sub-issues and all blocked-by edges verified

The historical dogfood report separately identifies its narrower 166-test handler/core experiment. It does not claim full Traverse execution, live Pi verification, MCP transport verification, or comparative productivity.

Boundaries

Documentation only: no source-execution permissions changed, no version bump, no tag/release, no deployments, and no automatic publication of project evidence. E01 must resolve and freeze the host-approval contract before dependent runtime work. Existing synthesis confirmation and Pi analysis guards remain intact.

Refs #398

[TheAmericanMaker]

Exact-head verification and merge readiness

Reviewed candidate: f8b030ec69b389b3592a7d3a5d84a274293bb028.

• CI run 35271416211 reports success for this exact head. Ubuntu Node 22 and 24 install, production audit, build, and tests passed.
• CodeQL actions and JavaScript/TypeScript analyses passed on the PR.
• The explicitly advisory test-windows job failed. Its ten failing test names exactly match the base-branch run 35247367515 at 1b473908d9db93a16a502cdea4212b435fdbdab3. The workflow marks that job continue-on-error; the known Windows work remains in atomicWriteFile: rename over an existing file fails with EPERM on Windows under concurrent writers #393, Pi write guard refuses a legitimate .codecarto/ write on Windows #394, and Tests: eight expectations assume POSIX paths and fail on Windows #395. No runtime or test files changed here.
• Committed file bytes match the staged objects checked for sensitive information and relative links. Git author/committer identity uses GitHub's public noreply address, not a workstation email.
• Independent publication review approved the candidate; independent plan review approved after the distribution-isolation obligation and E01 readiness clarification were added. Final issue-link replacements were checked to be mechanical only.

This merge publishes documentation and planning issues only. It does not close #398 or its implementation children and does not create a release.