Retire obsolete prototypes and consolidate current platform documentation

[utmist-tt]

Summary

Cleanup based on the department platform release now merged into main (3431ffd, PR #110), split into code and documentation commits.

Runtime and repository organization

• Retire the unused Redis scheduler/supervisor, old Docker executor, custom logger, prototype images/scripts, related fixtures, unused root module and editor artifact.
• Organize the current Kubernetes API into lifecycle, HTTP handlers, shared responses and job types; preserve current wire fields, authentication, team enforcement and historical account workloads.
• Add a root Go workspace for the API and CLI; tidy retired dependencies.
• Remove dummy CLI commands, unused frontend helpers/chart and unused Immer dependencies.
• Remove five outdated pre-team verifiers while retaining current department/storage/accelerator tooling and dated evidence.

Current documentation

• Add a documentation index and current k3s, Tailscale/OpenSSH, storage and development guides, verified against both machines.
• Update architecture, deployment, CLI, API and testing instructions; label and archive superseded guides while keeping old entry links useful.
• Remove the plaintext SSH password from the old guide. Git history retains it; the credential should be retired if still valid. No passwords or history were changed.
• Add reusable local Markdown link/anchor and shell-example syntax validation plus a sanitized cleanup report.

Verification

• 29 API tests and 6 CLI tests pass with race detection; no skipped tests. Go vet passes.
• Static API/CLI builds, CLI help and rejection of the retired executor pass.
• Compiler-based Go dead-code analysis, including tests, reports zero unreachable functions.
• 10 React tests, TypeScript, full frontend lint and production build pass. Dependency removal reported zero npm vulnerabilities.
• All 6 storage migration tests pass as root in a disposable container using tiny temporary files.
• 191 local documentation links/anchors and 34 current shell examples pass validation.
• The compiled candidate API passed four read-only checks against real Kubernetes/auth on a temporary localhost listener: health/startup, anonymous session, anonymous job denial and graceful SIGTERM. Team admission was disabled for this probe.
• Both live nodes, device operators, API/auth services, host services, SSH/Tailscale settings, LAN interfaces, agent token-file permissions, accelerator inventory and storage usage were inspected.

Operational scope

The running portal continues to use the previously verified department release. This PR does not redeploy or restart production, submit training, alter accounts/jobs/research files, prune host storage or perform large storage tests. Earlier CUDA/TT/browser/isolation evidence is explicitly release-specific rather than claimed as a new run of this candidate.

Start at the documentation index. Details and sanitized evidence are linked from the cleanup record.

Main requires an independent approving review. Squash merge respects its linear-history rule.

[github-actions]

This PR exceeds the recommended size of 1000 lines. Please make sure you are NOT addressing multiple issues with one PR. Note this PR might be rejected due to its size.