Scrubs internal-only references from cmd/lakebox/ in preparation for
this code shipping in a public CLI release:

- Drops employee-name attributions in code comments (config.go,
  list.go, start.go, state.go).
- Drops bug-bash form IDs (F10, F22) — the technical context they
  hung off stands on its own.
- Drops references to private-repo paths (lakebox/src/...,
  universe#1966484, lakebox.proto) and to internal SAFE flag names
  (lakeboxCheckerEnabled), internal subsystems (ESM, LakeboxChecker),
  and internal vocabulary (dogfood staging).
- Drops the "no prod listener yet" roadmap mention from
  resolveGatewayHost — advertising rollout state isn't useful to OSS
  readers.
- Fixes lakebox status help-text examples to include the `databricks`
  prefix for consistency with sibling commands.
- Removes internal/bugbash/ entirely (install.sh + exec.sh + README).
  The snapshot-install script was an internal coordination tool tied
  to the demo-lakebox branch lifecycle and doesn't belong in a public
  repo. The release-build workflow still triggers on `bugbash-*`
  branches as a benign CI convention.

No behavior change; pure comment + dead-file cleanup. Tests still pass.

Co-authored-by: Isaac

The previous commit deleted the entire `internal/bugbash/` directory,
but exec.sh and README.md predate the lakebox work — Pieter authored
them in databricks#1844 (May 2024), Lennart and Andrew extended them, and they
are linked via a public curl-pipe-bash URL that may be referenced
from internal Slack/docs. Removing them without consulting the
maintainers is out of scope for an OSS-comment-cleanup PR.

Only install.sh stays deleted: it was added in databricks#5359 specifically
to install the demo-lakebox snapshot, and the long-term home for
that script is no longer inside the public repo.

Co-authored-by: Isaac

Pass over every Go file in cmd/lakebox/ to bring comment density in
line with the repo style guide (comments explain WHY, not WHAT; default
to none). Net 152 lines removed.

What got cut:
- Pure noise that restated obvious code ("Use the dedicated lakebox
  SSH key.", "Check that ssh-keygen is available before trying to
  generate.", "Slice off the OpenSSH comment by stopping at the second
  space.", etc.).
- Multi-paragraph essays where one sentence was load-bearing.
- Duplicated explanations across function-doc and call-site, or
  across sibling functions (stop/start/registerKey, sandboxEntry/
  updateBody).
- Code-history narration ("used to render a hardcoded 10m...", "until
  this helper existed lakebox commands silently...").
- Signature restatements at the end of function docs.

What was preserved (the exemplars worth keeping):
- sandboxPath security context.
- idleTimeoutSecs Duration proto3 form.
- listPage SDK slot-6 quirk.
- verifyKeyRegistered SSH protocol limitation.
- buildSSHArgs ssh-arg-joining trap.
- removeSandbox orphan-gateway-host cleanup.
- buildSSHConfigBlock UI alignment + first-match-wins ordering.
- field SGR-before-padding invariant.

Added missing function-doc comments to New, loadState, saveState,
stateFilePath for consistency with the rest of the package.

No behavior change.

Co-authored-by: Isaac