Show real shell identity in Kandelo's default prompt

[brandonpayton]

Why

Kandelo's default shell prompt is currently a fixed kandelo$. It does
not show which account owns the shell or where that shell is working.
That makes sessions harder to understand today and will become
misleading as real login support introduces more than one user.

The kernel and root filesystem also report a generic hostname, while
the browser used to inject its own prompt. Shell identity should come
from the guest's real account, hostname, and working directory instead
of a presentation-layer substitute. Browser Guide commands also need
a reliable completion boundary because ordinary command output may
itself end in $ or # .

This change gives users a compact prompt that exposes the state they are
actually operating in:

user@kandelo ~/path ❯

What changed

• Set the kernel nodename and /etc/hostname default to kandelo.
• Add an interactive-Bash profile using Bash's \u, \h, and \w
  expansions, so the user, real hostname, and current directory stay
  dynamic.
• Render user and host in cyan, the directory in blue, and the prompt
  glyph in green for ordinary users or red for root.
• Keep a plain \u@\h \w \$ prompt for TERM=dumb and leave Dash and
  noninteractive shells unaffected.
• Remove the browser's synthetic PS1 and preserve exact configured
  prompts and conservative custom-shell readiness paths.
• Add OSC 133 prompt boundaries to the styled default. Once a session
  proves marker support, Guide commands wait for the trailing B
  boundary instead of accepting prompt-looking command output.
• Classify the current complete terminal-history suffix after
  synchronous replay. This also prevents completed readiness listeners
  from leaking.
• Advance the kernel, rootfs, shell, and source-image package revisions
  and regenerate the package projection so stale hostname or prompt
  artifacts cannot retain a valid identity.
• Document the user-visible hostname, prompt, privilege, fallback, and
  readiness contracts.

Node.js and browser hosts share the readiness implementation. The
Node.js source-image smoke test verifies the image-owned hostname and
profile. Chromium and WebKit exercise the visible prompt and terminal
command path.

This does not change the application binary interface (ABI), so
ABI_VERSION is unchanged.

Validation

Fresh final-tree checks through scripts/dev-shell.sh:

• kernel uname hostname unit: 1 passed, 1,248 filtered;
• focused readiness, session, rootfs, and source-image Vitest:
  130 passed;
• Chromium shell, Bash, Vim, and NetHack flow: 1 passed;
• WebKit shell-input flow: 1 passed;
• generated program-package projection: no drift;
• ABI snapshot, C header, and TypeScript bindings: consistent; and
• git diff --check origin/main...HEAD: clean.

Earlier validation on this branch also passed all 1,249 kernel unit
tests, the mandatory Node.js source-image smoke test, and manual
Chromium checks for the initial prompt, /tmp directory update, colors,
effective user, hostname, terminal focus, and Guide completion.

Two independent final reviews found no Critical, Important, or Minor
issues.

Known limitations

• The repository-wide Vitest inventory remains red with nine executed
  test failures and 21 collection failures. The recorded failures
  concern package provenance, artifact closure, unavailable fixtures,
  and existing runtime timeouts outside this prompt path.
• The two focused Sortix cases remain red with one failure and one
  timeout in the current artifact/runtime environment.
• The normal ./run.sh browser launcher stops before app launch because
  the Homebrew shell package still awaits its immutable bottle
  selection. The focused Chromium and WebKit runs above use coherent
  local artifacts.
• Broader browser inventories were not rerun. Performance was not
  measured.
• The existing environment still exports USER=player while the
  effective account is user. The prompt intentionally uses Bash's
  \u, which follows the effective account. Reconciling that
  environment variable belongs to the upcoming login work.

[github-actions]

Phase B-1 matrix build status — pr-1246-staging-run-31449474154-attempt-1

ABI v42. 0 built, 2 failed, 2 total.

Package	Arch	Status	Sha
kernel	wasm32	failed	—
rootfs	wasm32	failed	—

_{Auto-generated; replaced on each push. Raw data in the publish-status workflow artifact.}