feat: add logs command

fix: track algod spec instead of pinning a stale one

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

An entry with no readable level was dropped once the floor passed error,
which is the one place the exemption had to hold: a runtime panic is
written by the Go runtime and not through logrus, so it carries no level
field, and `logs --level panic` on a node that died of a nil dereference
answered with nothing at all while the default warn view showed the dump.
The floor now never judges a line it could not read a level from, which is
what the command's help has been promising.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PqPSx1wqM8rMdo4EHPa4jy

Size against offset only catches a truncation that is still visible when
the poll arrives. A file emptied and written back past the old offset
inside one interval never looks short, and the next drain reads new bytes
at a stale position: the prefix is lost and a pending fragment of the old
file is spliced onto what followed.

Polling has no way to close that. Nothing separates a truncate-and-regrow
from an append once the inode is unchanged and the length has recovered,
so the alternative is a different mechanism rather than a better check.
The window is one interval wide, algod rotates by renaming, and tail -F
has the same hole; it is left open on purpose, and now says so.

The truncation test slept to stay out of that window without explaining
which window, which read as timing noise rather than as the point.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PqPSx1wqM8rMdo4EHPa4jy

Every other registered top-level command has one, and the README's
command list is where the published docs link from. Generated with
cobra/doc and put through the same banner substitution the existing
pages carry, checked by regenerating nodekit_restart.md and diffing it
against the committed copy.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NMKTAqwAPrGqB8hvgmBWu5

The message broke off at "adding your account to the 'algorand' group
after", and it blamed the algod data directory's ownership for every
permission failure, including one on a file the user named with --file. It
now finishes the instruction, and a file the user chose gets a message that
only says which path could not be read.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PqPSx1wqM8rMdo4EHPa4jy

Scan reported the live log's size as the follow offset, but a log caught
mid-write ends mid-line: the scan shows that fragment, and Follow then
resumed past it, so the remainder of the line arrived as a line of its own
and the entry algod was writing never appeared whole. The offset is now
rounded back to the last line boundary, within one read buffer, so the
completed entry is delivered once the newline lands.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PqPSx1wqM8rMdo4EHPa4jy