Add the Tazel plugin catalog of ViGet to the API

ViGet opens in stages: first only Progmasoft publishes Tazel plugins, later
every account. This adds the catalog and the server-side publishing for the
first stage; nothing publishes through the API yet.

- ViGet/: the catalog of Tazel plugins (in memory, or in PostgreSQL beside
  the accounts with its own numbered schema steps), the descriptor read from
  the JAR (META-INF/tazel-plugin.properties, with a reader of the Java
  properties format, and the ProjectPlugin service entry), and publishing:
  the publisher must be in ViGet:TazelPublishers (Progmasoft for now) and an
  existing account of that exact name, a version is never replaced, names
  that differ only in letter case are refused, and ViGet needs a
  description, an author and a license. The JAR is kept at
  dslplugins/tazel/<Publisher>/<Name>/<Version>/<Name>-<Version>.jar below
  ViGet:ArtifactRoot.
- Read endpoints under /api/v1/viget/dslplugins/tazel: the list, a plugin,
  and index.json, the index Tazel reads.
- 'viget publish-tazel-plugin <jar>' and 'viget yank-tazel-plugin' run with
  the configuration of the service instead of the service.
- The account store can find an account by name.

The pages, the Nginx routes and the deployment follow.

1 files changed, 149 insertions, 0 deletions

diff --git a/apps/api/ViGet/JavaProperties.cs b/apps/api/ViGet/JavaProperties.cs
new file mode 100644
index 0000000..e55991e
--- /dev/null
+++ b/apps/api/ViGet/JavaProperties.cs
@@ -0,0 +1,149 @@
+// SPDX-FileCopyrightText: 2026 Progmasoft <support@progmasoft.com>
+// SPDX-License-Identifier: AGPL-3.0-or-later WITH AdditionRef-Progmasoft-Patent-Grant-1.1
+
+using System.Globalization;
+using System.Text;
+
+namespace Progmasoft.Progmaweb.Api.ViGet;
+
+/// <summary>Reads the text of a Java <c>.properties</c> file, as <c>java.util.Properties.load</c> does.</summary>
+/// <remarks>
+/// A logical line may continue over several lines with a trailing backslash; <c>#</c> and <c>!</c> start a comment
+/// line; a key ends at the first unescaped <c>=</c>, <c>:</c> or white space; and <c>\t</c>, <c>\n</c>, <c>\r</c>,
+/// <c>\f</c> and <c>\uXXXX</c> are escapes, while a backslash before any other character stands for that character.
+/// A later line with the same key replaces an earlier one.
+/// </remarks>
+internal static class JavaProperties
+{
+    /// <summary>Reads the properties of a text.</summary>
+    /// <param name="text">The text of the file, already decoded.</param>
+    /// <returns>The properties by key.</returns>
+    /// <exception cref="FormatException">A <c>\u</c> escape is not followed by four hexadecimal digits.</exception>
+    public static IReadOnlyDictionary<string, string> Parse(string text)
+    {
+        Dictionary<string, string> properties = new(StringComparer.Ordinal);
+        foreach (string line in LogicalLines(text))
+        {
+            int index = 0;
+            while (index < line.Length && IsBlank(line[index]))
+            {
+                index++;
+            }
+
+            if (index == line.Length || line[index] is '#' or '!')
+            {
+                continue;
+            }
+
+            int keyStart = index;
+            while (index < line.Length && !IsKeyEnd(line[index]))
+            {
+                index += line[index] == '\\' ? 2 : 1;
+            }
+
+            string key = Unescape(line[keyStart..Math.Min(index, line.Length)]);
+            while (index < line.Length && IsBlank(line[index]))
+            {
+                index++;
+            }
+
+            if (index < line.Length && line[index] is '=' or ':')
+            {
+                index++;
+                while (index < line.Length && IsBlank(line[index]))
+                {
+                    index++;
+                }
+            }
+
+            properties[key] = Unescape(line[index..]);
+        }
+
+        return properties;
+    }
+
+    /// <summary>Joins the physical lines that a trailing backslash continues.</summary>
+    private static IEnumerable<string> LogicalLines(string text)
+    {
+        string[] lines = text.Replace("\r\n", "\n", StringComparison.Ordinal).Replace('\r', '\n').Split('\n');
+        StringBuilder current = new();
+        bool continuing = false;
+        foreach (string physical in lines)
+        {
+            // A continued line loses the white space it starts with.
+            string line = continuing ? physical.TrimStart(' ', '\t', '\f') : physical;
+            int backslashes = 0;
+            for (int position = line.Length - 1; position >= 0 && line[position] == '\\'; position--)
+            {
+                backslashes++;
+            }
+
+            continuing = backslashes % 2 == 1;
+            current.Append(continuing ? line[..^1] : line);
+            if (!continuing)
+            {
+                yield return current.ToString();
+                current.Clear();
+            }
+        }
+
+        if (current.Length > 0)
+        {
+            yield return current.ToString();
+        }
+    }
+
+    private static bool IsBlank(char character) => character is ' ' or '\t' or '\f';
+
+    private static bool IsKeyEnd(char character) => character is '=' or ':' || IsBlank(character);
+
+    private static string Unescape(string text)
+    {
+        StringBuilder result = new(text.Length);
+        for (int index = 0; index < text.Length; index++)
+        {
+            char character = text[index];
+            if (character != '\\' || index + 1 == text.Length)
+            {
+                result.Append(character);
+                continue;
+            }
+
+            char escaped = text[++index];
+            switch (escaped)
+            {
+                case 't':
+                    result.Append('\t');
+                    break;
+                case 'n':
+                    result.Append('\n');
+                    break;
+                case 'r':
+                    result.Append('\r');
+                    break;
+                case 'f':
+                    result.Append('\f');
+                    break;
+                case 'u':
+                    if (text.Length - index - 1 < 4 ||
+                        !int.TryParse(
+                            text.AsSpan(index + 1, 4),
+                            NumberStyles.AllowHexSpecifier,
+                            CultureInfo.InvariantCulture,
+                            out int code))
+                    {
+                        throw new FormatException("A \\u escape needs four hexadecimal digits.");
+                    }
+
+                    result.Append((char)code);
+                    index += 4;
+                    break;
+                default:
+                    result.Append(escaped);
+                    break;
+            }
+        }
+
+        return result.ToString();
+    }
+}