Show the exact build in About, Copy Info, REPORT and --version

Builds from main reported only the release version (2026.36) even when
HEAD was hundreds of commits past the tag. build.rs now also emits
OCS_TAG_DISTANCE, OCS_COMMIT_DATE, OCS_BUILD_METADATA and
OCS_FULL_VERSION: a clean checkout of the release tag stays "2026.36",
anything else becomes "2026.36+194.gef189d77", with ".dirty" appended
for uncommitted changes and only the hash when no tag can be counted
from (shallow clone, tarball). OCS_APP_VERSION is unchanged so the
update check, donation gate, User-Agents and window title keep working.

The About dialog gains Build / Commit date / Profile cards, Copy Info,
the REPORT issue template and recovery reports carry the full version,
and `-V`/`--version` print it instead of Cargo's 2026.36.0. Release
workflows check out full history so release binaries see the tag.

Also fixes the build being marked dirty when there is no repository:
diff-index exits 128 there, not 1.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/cli.rs

@@ -20,7 +20,14 @@ use clap::Parser;
 #[derive(Parser, Debug, Default)]
 #[command(
     name = "OpenCADStudio",
-    version,
+    version = env!("OCS_FULL_VERSION"),
+    long_version = concat!(
+        env!("OCS_FULL_VERSION"),
+        "\nrevision: ", env!("OCS_GIT_REV"),
+        "\ncommit date: ", env!("OCS_COMMIT_DATE"),
+        "\nprofile: ", env!("OCS_BUILD_PROFILE"),
+        "\nfeatures: ", env!("OCS_BUILD_FEATURES"),
+    ),
     about = crate::t!("Open CAD Studio — 2D/3D CAD editor").into_owned(),
     long_about = None,
 )]