feat(kebab-cli): kebab schema subcommand (fb-27)

Text mode: doctor-style key/value layout. JSON mode: schema.v1 wire
record. Honors `--config <path>` via the established
`kebab_app::schema_with_config(&cfg)` facade pattern (per the P3-5 /
P4-3 regression conventions).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/kebab-cli/src/main.rs

@@ -177,6 +177,9 @@ enum Cmd {
     /// Health check.
     Doctor,
 
+    /// Print introspection report (wire schemas, capabilities, model versions, stats).
+    Schema,
+
     /// Launch the Ratatui shell (P9-1 — Library pane only; search /
     /// ask / inspect panes land with p9-2 / p9-3 / p9-4).
     Tui,
@@ -604,6 +607,18 @@ fn run(cli: &Cli) -> anyhow::Result<()> {
             Ok(())
         }
 
+        Cmd::Schema => {
+            let cfg = kebab_config::Config::load(cli.config.as_deref())?;
+            let report = kebab_app::schema_with_config(&cfg)?;
+            if cli.json {
+                let v = wire::wire_schema(&report);
+                println!("{}", serde_json::to_string(&v)?);
+            } else {
+                print_schema_text(&report);
+            }
+            Ok(())
+        }
+
         Cmd::Doctor => {
             let report = kebab_app::doctor_with_config_path(cli.config.as_deref())?;
             if cli.json {
@@ -720,6 +735,49 @@ fn run(cli: &Cli) -> anyhow::Result<()> {
     }
 }
 
+fn print_schema_text(s: &kebab_app::SchemaV1) {
+    println!("kebab v{}\n", s.kebab_version);
+
+    println!("wire schemas");
+    println!("  {}", s.wire.schemas.join(", "));
+    println!();
+
+    println!("capabilities");
+    let caps = [
+        ("json_mode", s.capabilities.json_mode),
+        ("ingest_progress", s.capabilities.ingest_progress),
+        ("ingest_cancellation", s.capabilities.ingest_cancellation),
+        ("rag_multi_turn", s.capabilities.rag_multi_turn),
+        ("search_cache", s.capabilities.search_cache),
+        ("incremental_ingest", s.capabilities.incremental_ingest),
+        ("streaming_ask", s.capabilities.streaming_ask),
+        ("http_daemon", s.capabilities.http_daemon),
+        ("mcp_server", s.capabilities.mcp_server),
+        ("single_file_ingest", s.capabilities.single_file_ingest),
+    ];
+    for (name, on) in caps {
+        let mark = if on { "✓" } else { "✗" };
+        println!("  {mark} {name}");
+    }
+    println!();
+
+    println!("models");
+    println!("  parser_version          {}", s.models.parser_version);
+    println!("  chunker_version         {}", s.models.chunker_version);
+    println!("  embedding_version       {}", s.models.embedding_version);
+    println!("  prompt_template_version {}", s.models.prompt_template_version);
+    println!("  index_version           {}", s.models.index_version);
+    println!("  corpus_revision         {}", s.models.corpus_revision);
+    println!();
+
+    println!("stats");
+    println!("  doc_count               {}", s.stats.doc_count);
+    println!("  chunk_count             {}", s.stats.chunk_count);
+    println!("  asset_count             {}", s.stats.asset_count);
+    let last = s.stats.last_ingest_at.as_deref().unwrap_or("(never)");
+    println!("  last_ingest_at          {last}");
+}
+
 /// Minimal stdin/stdout confirm prompt for destructive ops. No new dep —
 /// uses stdlib `IsTerminal` (the caller is expected to have already
 /// short-circuited the non-TTY case). Returns `Ok(true)` only when the