docs(build): correct terminal output + error code in build logs spec

Addresses CodeRabbit: a clean end prints nothing (not 'End of build log.'); the 404 code is BUILD_NOT_FOUND, not NOT_FOUND.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: kristof-siket

docs/product/command-spec.md

@@ -1539,11 +1539,11 @@ Behavior:
 - requires auth; authorizes against the workspace that owned the build when it ran (build logs can contain secrets, so access stays with that workspace)
 - takes a build id — shown in the Console build view and in git-push output; this is a build id, distinct from a runtime deployment id (`prisma-cli app logs` streams a deployment's runtime logs; this streams a build's logs)
 - streams the build's log records to stdout in human mode (each line carries its source — `runner` / `stdout` / `stderr` — and the build step); `stderr` and error-level records are written to stderr so stdout stays redirectable to a clean build log
-- ends with a terminal line: `End of build log.`, or `No build logs are available for this build.`
+- a clean end prints no trailing line; a build with no recorded logs prints `No build logs are available for this build.`, and read errors print their message (these terminal messages are written to stderr)
 - `--follow` keeps the connection open and streams new lines while an in-flight build runs; it ends on its own once the build reaches a terminal state
 - `--cursor <cursor>` resumes from a prior terminal cursor
 - `--json` emits one JSON event per record, ending in a terminal record (no trailing wrapper success event)
-- returns an indistinguishable `NOT_FOUND` when the build does not exist or the caller's workspace does not own it
+- returns an indistinguishable `BUILD_NOT_FOUND` when the build does not exist or the caller's workspace does not own it
 
 Examples: