Make spacetime describe support human-readable versions

codex-plugin/plugins/spacetimedb/skills/cli/SKILL.md

@@ -81,9 +81,11 @@ spacetime logs my-database -f              # follow logs
 spacetime logs my-database -n 100          # up to 100 log lines
 
 # Describe schema
+# (without --json, output is human-readable text)
 spacetime describe my-database --json
-spacetime describe my-database table users --json
-spacetime describe my-database reducer my_reducer --json
+spacetime describe my-database tables --json   # also reducers, procedures, types
+spacetime describe my-database tables users --json
+spacetime describe my-database reducers my_reducer --json
 ```
 
 ### Database Management

crates/cli/src/common_args.rs

@@ -8,6 +8,25 @@ pub enum ClearMode {
     Never,      // parses as "never"
 }
 
+#[derive(Clone, Copy, PartialEq)]
+pub enum Format {
+    Text,
+    Json,
+}
+
+impl clap::ValueEnum for Format {
+    fn value_variants<'a>() -> &'a [Self] {
+        &[Self::Text, Self::Json]
+    }
+
+    fn to_possible_value(&self) -> Option<clap::builder::PossibleValue> {
+        match self {
+            Self::Text => Some(clap::builder::PossibleValue::new("text").aliases(["default", "txt"])),
+            Self::Json => Some(clap::builder::PossibleValue::new("json")),
+        }
+    }
+}
+
 pub fn server() -> Arg {
     Arg::new("server")
         .long("server")
@@ -30,6 +49,15 @@ pub fn yes() -> Arg {
         .help("Run non-interactively wherever possible. This will answer \"yes\" to almost all prompts, but will sometimes answer \"no\" to preserve non-interactivity (e.g. when prompting whether to log in with spacetimedb.com).")
 }
 
+/// The `--format` arg, parsed as a [`Format`]. Callers supply their own `.help(...)`.
+pub fn format() -> Arg {
+    Arg::new("format")
+        .long("format")
+        .default_value("text")
+        .required(false)
+        .value_parser(value_parser!(Format))
+}
+
 pub fn confirmed() -> Arg {
     Arg::new("confirmed")
         .required(false)