feat: restore issue-tracker console script as migration hint

Callers using the pre-rename `issue-tracker` command now get a clear
stderr message pointing them at `issue-core` (or the short `issue`
alias) and exit code 2, instead of `command not found`.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

issue_core/cli/legacy.py

@@ -0,0 +1,18 @@
+"""
+Legacy entry-point shims for renamed console scripts.
+
+Kept so that callers using the pre-rename names get a clear, loud migration
+hint instead of `command not found`.
+"""
+
+import sys
+
+
+def issue_tracker_hint() -> None:
+    """`issue-tracker` -> `issue-core` migration hint."""
+    sys.stderr.write(
+        "issue-tracker has been renamed to issue-core.\n"
+        "  - Run `issue-core <args>` (or the short alias `issue <args>`) instead.\n"
+        "  - The Python package is now `issue_core` (was `issue_tracker`).\n"
+    )
+    sys.exit(2)

pyproject.toml

@@ -78,6 +78,7 @@ Repository = "https://github.com/coulomb/issue-core.git"
 [project.scripts]
 issue = "issue_core.cli.main:main"
 issue-core = "issue_core.cli.main:main"
+issue-tracker = "issue_core.cli.legacy:issue_tracker_hint"
 
 [tool.setuptools.packages.find]
 include = ["issue_core*"]