contrib header changes

HEADER.txt

@@ -0,0 +1,50 @@
+Project source file header template
+===================================
+
+Place this block at the top of each source unit (after optional shebang / <?php).
+Run `python3 scripts/apply-project-headers.py` to (re)apply across the tree.
+Install git hooks: `./scripts/install-git-hooks.sh`
+
+Excluded paths: `third-party/` and build/vendor dirs are never modified.
+
+Pre-commit contributor (email auto-filled from git when missing):
+  export HEADER_CONTRIBUTOR="Your Name"          # adds git user.email
+  export HEADER_CONTRIBUTOR="Name <you@mail>"    # used as-is
+  export HEADER_CONTRIBUTOR_EMAIL="you@mail"     # optional override
+
+Placeholders
+------------
+__PACKAGE_NAME_PLACEHOLDER__
+  Java/AIDL: `package com.example.foo;`
+  C/C++/PHP: `/* package path/relative/to/repo/file.ext */`
+
+__FILENAME_PLACEHOLDER__     Short filename only (e.g. MainActivity.java)
+
+__DATE_PLACEHOLDER__           First commit time (human-readable + timezone)
+
+__UPDATE_DATE_PLACEHOLDER__    Last change time; pre-commit refreshes on staged edits
+
+__CONTRIBUTOR__                `Name <email>` when known (git log/config); else `Name`
+
+__CLASS_NAME_PLACEHOLDER__     ` * class Foo` / interface / enum — omitted if none
+
+__CONTRIBUTORS_LIST_PLACEHOLDER__
+  Sorted by commits, then blamed lines; `Name <email>` from git / @author tags
+  Includes Cursor Agent (project assistant, no email)
+
+__DIGEST__                     `Digest: SHA256\t<hex>` of file without this line; omitted if N/A
+
+Example (Java)
+--------------
+package com.foxx.androidcast;
+
+/*********************************************************************
+ * MainActivity.java
+ * Created at: Wed 20 May 2026 12:00:00 +0300
+ * Updated at: Wed 20 May 2026 15:00:00 +0300 by Anton Afanasyeu <a.afanasieff@gmail.com>
+ * class MainActivity
+ * Contributors:
+ *    - Anton Afanasyeu <a.afanasieff@gmail.com> (29 commits, 120 lines)
+ *    - Cursor Agent (project assistant)
+ * Digest: SHA256	abc123...
+**********************************************************************/