halkyon_base: a Serverpod module for sign-in, accounts and instance basics

What every Halkyon server has, taken from Halkyon Learn's: anonymous,
GitHub and email-code sign-in with their endpoints, an account's ways
in and its deletion, the pruning of abandoned anonymous people, of
sign-up attempts and of expired codes, and the instance's basics (the
sign-in ways offered, the source link, the minimum app build, where
people's data and its backups are). Endpoints sit under the nickname
`base`. A host configures it in one place before its pod starts: its
name for the mails, its source link, its minimum build, and hooks that
delete its own data with a person.

The tables keep Learn's names, columns and indexes, so a host moving
onto the module migrates nothing but version rows. Server package under
the SSPL, client under the AGPL, as Learn's are.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

packages/halkyon_base_server/.gitignore

@@ -0,0 +1,19 @@
+# Files and directories created by pub
+.dart_tool/
+.packages
+
+# Omit committing pubspec.lock for library packages:
+# https://dart.dev/guides/libraries/private-files#pubspeclock
+pubspec.lock
+
+# Conventional directory for build outputs
+build/
+
+# Directory created by dartdoc
+doc/api/
+
+# Passwords file: the tests' throwaway values, never committed.
+config/passwords.yaml
+
+# Embedded PostgreSQL runtime artifacts (data dir, sockets, pidfiles)
+.serverpod/