feat(launcher-standard): require --version mode with machine-greppable format (#173)

## Summary

The launcher-standard requires `--help` but not `--version`, so
launchers
had no obligation to emit a version string. Result: field bug reports
consistently lack a build identity ("it's broken on my machine" with no
SHA, no way to bisect, no way to tell two builds apart).

This adds `--version` (and the alias `-V`) to the required meta-modes.
The first line of output MUST follow a machine-greppable format:

\`\`\`
{app-name} {version} ({build-sha-short}) [{platform}]
\`\`\`

Example: `aerie-launcher 0.4.2 (a1b2c3d) [linux-x86_64]`

Additional lines (build date, runtime versions, dep summary) MAY follow.
Exit code MUST be 0 on success.

## Changes

- **`launcher/launcher-standard.a2ml`**: added `--version` to
  `[required-modes].meta`; added new `[version-output]` table specifying
  the first-line format, an example, exit code, and machine-greppable
  flag.
- **`docs/UX-standards/launcher-standard.adoc`**: added a row to the
  §Required Modes table describing `--version` / `-V`, the format, and
  the rationale.

Both files updated in the same commit per the §Sync requirement and the
lock-step CI gate (PR #172) — this PR is a good first live test of that
gate.

## Test plan

- [x] a2ml parses (python tomllib): `meta = ['--help', '--version']`,
      `[version-output]` round-trips with all four fields intact.
- [x] AsciiDoc table renders (visual — added one row, no structural
      changes).
- [ ] Lock-step gate (#172) goes green on this PR's first push (both
      files in diff).

## Coordination

- Independent of #170, #171, #172. The lock-step gate runs on every PR
  touching either of the two group files, so this PR will be one of
  the first live exercises of that gate once #172 lands.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

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.