Replace lyaml with api7-lua-tinyyaml and prepare the 0.1.0 releasev0.1.0

lyaml binds the system libyaml, which luarocks does not vendor, so
installing the rock failed wherever that library was absent, taking the
whole extension down on a stock macOS machine. api7-lua-tinyyaml is pure
Lua and matches lyaml on every quoting, escaping and block-scalar form
profiles use.

What the subset costs: anchors and aliases are not resolved, and plain
multi-line scalars raise. The raise surfaces through the existing parse
warning, but an unresolved alias came back as the literal "*alias"
string and would have become a profile name, so frontmatter.parse now
detects those keys, drops them, and warns.

Point source.url at code.tjp.lol with a v0.1.0 tag, replacing a GitHub
URL that never existed. Add a LICENSE file and mise release tasks, and
fix the README dependency-install command, which called a luarocks.cmd
function that does not exist.

1 files changed, 25 insertions, 19 deletions

diff --git a/spec/test_frontmatter.lua b/spec/test_frontmatter.lua
index 3f0c4c5..f729254 100644
--- a/spec/test_frontmatter.lua
+++ b/spec/test_frontmatter.lua
@@ -2,18 +2,18 @@
 --
 -- The body is the part a broken header must never cost the user, so every
 -- degraded case is checked for "body preserved verbatim" as well as for the
--- warning. Cases that actually parse YAML need lyaml and skip without it.
+-- warning. Cases that actually parse YAML need tinyyaml and skip without it.
 
 local frontmatter = require("subagents.frontmatter")
 
-local function lyaml_or_skip()
-    return pcall(require, "lyaml")
+local function yaml_or_skip()
+    return pcall(require, "tinyyaml")
 end
 
 return {
     { "fenced header parses and keeps the body verbatim", function()
-        if not lyaml_or_skip() then
-            return "skip", "lyaml is not installed"
+        if not yaml_or_skip() then
+            return "skip", "tinyyaml is not installed"
         end
         local body = "You are a reviewer.\n\n  indented line  \n"
         local data, parsed_body, warning = frontmatter.parse(
@@ -27,8 +27,8 @@ return {
     end },
 
     { "CRLF fences are tolerated", function()
-        if not lyaml_or_skip() then
-            return "skip", "lyaml is not installed"
+        if not yaml_or_skip() then
+            return "skip", "tinyyaml is not installed"
         end
         local data, body, warning = frontmatter.parse("---\r\nname: crlf\r\n---\r\nbody\r\n")
         assert(warning == nil, tostring(warning))
@@ -59,26 +59,32 @@ return {
         assert(warning == nil, tostring(warning))
     end },
 
-    { "broken YAML warns and keeps the body", function()
-        if not lyaml_or_skip() then
-            return "skip", "lyaml is not installed"
+    { "a header the parser rejects warns and keeps the body", function()
+        if not yaml_or_skip() then
+            return "skip", "tinyyaml is not installed"
         end
-        local data, body, warning = frontmatter.parse("---\na: [unclosed\n---\nbody\n")
-        assert(data == nil, "a broken header must not produce metadata")
+        local data, body, warning = frontmatter.parse("---\njust a string\n---\nbody\n")
+        assert(data == nil, "a rejected header must not produce metadata")
         assert(body == "body\n", string.format("%q", body))
         assert(type(warning) == "string" and warning:find("did not parse", 1, true),
             "expected a parse warning, got " .. tostring(warning))
     end },
 
-    { "a non-mapping document warns and keeps the body", function()
-        if not lyaml_or_skip() then
-            return "skip", "lyaml is not installed"
+    { "an unresolved alias is dropped rather than read literally", function()
+        if not yaml_or_skip() then
+            return "skip", "tinyyaml is not installed"
         end
-        local data, body, warning = frontmatter.parse("---\njust a string\n---\nbody\n")
-        assert(data == nil, "a scalar header must not produce metadata")
+        -- tinyyaml does not resolve aliases: without the guard in parse(), the
+        -- `*d` token would arrive as the literal string "*d" and become this
+        -- profile's name.
+        local data, body, warning = frontmatter.parse(
+            "---\ndefs: &d my-agent\nname: *d\n---\nbody\n")
+        assert(type(data) == "table", "the mapping itself should survive")
+        assert(data.name == nil, "an alias must not become a value, got " .. tostring(data.name))
+        assert(data.defs == nil, "an anchor must not become a value, got " .. tostring(data.defs))
         assert(body == "body\n", string.format("%q", body))
-        assert(type(warning) == "string" and warning:find("not a mapping", 1, true),
-            "expected a mapping warning, got " .. tostring(warning))
+        assert(type(warning) == "string" and warning:find("anchors/aliases", 1, true),
+            "expected an alias warning, got " .. tostring(warning))
     end },
 
     { "empty input is empty output", function()