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>

locales/cs-CZ/opencadstudio.ftl

@@ -4606,6 +4606,8 @@ plugins =
     .no-releases = žádná vydání
 
 ui =
+    .build = Sestavení
+    .commit-date = Datum commitu
     .count-steps-available = K dispozici jsou kroky __ocs_arg_count__
     .label-history = Historie __ocs_arg_label__
     .n-vp = __ocs_arg_n__ VP
@@ -4705,6 +4707,7 @@ ui =
     .quick-select-menu-period-title-case = Rychlý výběr...
     .reading-file = Čtení souboru…
     .redo = Znovu
+    .release = Vydání
     .repeat-last = Opakujte __ocs_arg_last__
     .replace-all = Nahradit vše
     .replace-with = Nahradit za: