feat(launcher-standard): require --version mode with machine-greppable format

docs/UX-standards/launcher-standard.adoc

@@ -170,6 +170,14 @@ fi
 | `--help` / `-h`
 | Print usage text, including a description of every mode, the files the
   launcher reads/writes, and the detected platform.
+
+| `--version` / `-V`
+| Print the launcher's version on a single machine-greppable first line,
+  then exit 0. Format: `<app-name> <version> (<build-sha-short>) [<platform>]`
+  (e.g. `aerie-launcher 0.4.2 (a1b2c3d) [linux-x86_64]`). Additional lines
+  (build date, runtime versions) MAY follow. Required so field bug reports
+  can quote a specific build — a launcher without `--version` produces
+  unactionable issues.
 |===
 
 NOTE: `--integ` and `--disinteg` replace the earlier pattern of separate

launcher/launcher-standard.a2ml

@@ -46,7 +46,20 @@ final-shell       = "bash -l at REPO_DIR (never 'press enter to close')"
 # These are the modes every compliant launcher MUST implement.
 runtime = ["--start", "--stop", "--status", "--auto", "--browser"]
 integration = ["--integ", "--disinteg"]
-meta = ["--help"]
+meta = ["--help", "--version"]
+
+[version-output]
+# Required format for the `--version` mode. The first line MUST be
+# machine-greppable so field bug reports can quote it verbatim. Optional
+# additional lines (build SHA, build date, libc / runtime versions) MAY
+# follow on subsequent lines.
+#
+# Rationale: a launcher with no --version produces unactionable bug
+# reports — "it's broken on my machine" with no way to tell which build.
+first-line-format = "{app-name} {version} ({build-sha-short}) [{platform}]"
+example          = "aerie-launcher 0.4.2 (a1b2c3d) [linux-x86_64]"
+exit-code        = 0
+machine-greppable = true
 
 [optional-modes]
 # Modes launchers MAY implement for extra functionality.