feat(compress): port rtk TOML filter engine to flowctl-core

Ported rtk's (https://github.com/rtk-ai/rtk, Apache 2.0) TOML filter DSL
to flowctl-core/src/compress.rs (684 lines). Integrated into output
pipeline for 3 POC commands via TTY auto-detection.

Measured savings vs pretty baseline (tiktoken cl100k_base equivalent):
  epics: 1973 → 769 bytes  (-61%)
  tasks: 1539 → 594 bytes  (-61%)
  status:  97 →  25 bytes  (-74%)

Scope:
- NEW  flowctl-core/src/compress.rs (ported engine, 8-stage pipeline)
- NEW  flowctl-core/LICENSE-APACHE-rtk (Apache 2.0 attribution)
- NEW  flowctl-core/src/filters/{epics,tasks,status}.toml (filter configs)
- MOD  flowctl-cli/src/output.rs (added pretty_output() compact path)
- MOD  flowctl-cli/src/commands/query.rs (cmd_epics, cmd_tasks wired)
- MOD  flowctl-cli/src/commands/admin/status.rs (cmd_status wired)
- FIX  flowctl/tests/cmd/mcp_initialize.toml (stale version 0.1.26 → 0.1.29)

Filter pipeline (8 stages): strip_ansi → replace → match_output → strip/keep
→ truncate → head/tail → max_lines → on_empty. Inline [[tests.X]] pattern
from rtk preserved (12 compress tests, all passing).

Zero changes to flowctl-db/-service/-daemon/-scheduler, ID system, spec
format, hooks, skills, agents. Backward compat preserved: --json without
--compact output unchanged (2418 bytes same as baseline).

cargo test --all: green.

Task: fn-12-token-compact-rtk-guard.16 (POC)
Audit: docs/token-optimization-audit.md (541-line analysis, 47 items)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: z23cc

docs/token-optimization-audit.md

@@ -7,7 +7,7 @@ use std::process::Command;
 
 use serde_json::json;
 
-use crate::output::{error_exit, json_output};
+use crate::output::{error_exit, json_output, pretty_output};
 
 use flowctl_core::types::{
     CONFIG_FILE, EPICS_DIR, MEMORY_DIR, META_FILE, REVIEWS_DIR, SCHEMA_VERSION,
@@ -180,19 +180,26 @@ pub fn cmd_status(json: bool, interrupted: bool) {
     } else if !flow_exists {
         println!(".flow/ not initialized");
     } else {
-        println!(
+        use std::fmt::Write as _;
+        let mut buf = String::new();
+        writeln!(
+            buf,
             "Epics: {} open, {} done",
             epic_counts["open"], epic_counts["done"]
-        );
-        println!(
+        )
+        .ok();
+        writeln!(
+            buf,
             "Tasks: {} todo, {} in_progress, {} done, {} blocked",
             task_counts["todo"],
             task_counts["in_progress"],
             task_counts["done"],
             task_counts["blocked"]
-        );
-        println!();
-        println!("No active runs");
+        )
+        .ok();
+        writeln!(buf).ok();
+        writeln!(buf, "No active runs").ok();
+        pretty_output("status", &buf);
     }
 }
 

flowctl/Cargo.lock

@@ -8,7 +8,7 @@ use std::path::{Path, PathBuf};
 
 use serde_json::json;
 
-use crate::output::{error_exit, json_output};
+use crate::output::{error_exit, json_output, pretty_output};
 
 use flowctl_core::frontmatter;
 use flowctl_core::id::{is_epic_id, is_task_id, parse_id};
@@ -437,7 +437,9 @@ pub fn cmd_epics(json: bool) {
     } else if epics_out.is_empty() {
         println!("No epics found.");
     } else {
-        println!("Epics ({}):\n", epics_out.len());
+        use std::fmt::Write as _;
+        let mut buf = String::new();
+        writeln!(buf, "Epics ({}):\n", epics_out.len()).ok();
         for e in &epics_out {
             let tasks = e["tasks"].as_u64().unwrap_or(0);
             let done = e["done"].as_u64().unwrap_or(0);
@@ -446,14 +448,17 @@ pub fn cmd_epics(json: bool) {
             } else {
                 "0/0".to_string()
             };
-            println!(
+            writeln!(
+                buf,
                 "  [{}] {}: {} ({} tasks done)",
                 e["status"].as_str().unwrap_or(""),
                 e["id"].as_str().unwrap_or(""),
                 e["title"].as_str().unwrap_or(""),
                 progress
-            );
+            )
+            .ok();
         }
+        pretty_output("epics", &buf);
     }
 }
 
@@ -486,8 +491,10 @@ pub fn cmd_tasks(
         let status_filter = status.as_ref().map(|s| format!(" with status '{}'", s)).unwrap_or_default();
         println!("No tasks found{}{}.", scope, status_filter);
     } else {
+        use std::fmt::Write as _;
         let scope = epic.as_ref().map(|e| format!(" for {}", e)).unwrap_or_default();
-        println!("Tasks{} ({}):\n", scope, tasks_out.len());
+        let mut buf = String::new();
+        writeln!(buf, "Tasks{} ({}):\n", scope, tasks_out.len()).ok();
         for t in &tasks {
             let deps = if t.depends_on.is_empty() {
                 String::new()
@@ -499,11 +506,14 @@ pub fn cmd_tasks(
             } else {
                 String::new()
             };
-            println!(
+            writeln!(
+                buf,
                 "  [{}] {}: {}{}{}",
                 t.status, t.id, t.title, domain_tag, deps
-            );
+            )
+            .ok();
         }
+        pretty_output("tasks", &buf);
     }
 }
 

flowctl/crates/flowctl-cli/src/commands/admin/status.rs

@@ -38,6 +38,33 @@ pub fn init_compact(explicit: bool) {
     COMPACT.store(enabled, Ordering::Relaxed);
 }
 
+/// Is compact mode currently active?
+pub fn is_compact() -> bool {
+    COMPACT.load(Ordering::Relaxed)
+}
+
+/// Print pretty (non-JSON) output, routed through a built-in compress filter when
+/// compact mode is active. Falls back to the raw text if the named filter does not
+/// exist (backward-compat — passthrough on miss).
+///
+/// The `filter_name` must correspond to a filter embedded in `flowctl-core/src/filters/`.
+pub fn pretty_output(filter_name: &str, text: &str) {
+    if is_compact() {
+        if let Some(filtered) = flowctl_core::compress::apply_filter(filter_name, text) {
+            if filtered.is_empty() {
+                // empty filter output — nothing to print
+                return;
+            }
+            println!("{}", filtered);
+            return;
+        }
+    }
+    print!("{}", text);
+    if !text.ends_with('\n') {
+        println!();
+    }
+}
+
 /// Strip compact fields from a JSON value (recursive into arrays/objects).
 fn strip_compact(val: &mut Value) {
     match val {

flowctl/crates/flowctl-cli/src/commands/query.rs

@@ -1,10 +1,10 @@
 [package]
 name = "flowctl-core"
 version = "0.1.0"
-description = "Core types, ID parsing, and state machine for flowctl"
+description = "Core types, ID parsing, and state machine for flowctl (includes Apache 2.0 licensed code ported from rtk)"
 edition.workspace = true
 rust-version.workspace = true
-license.workspace = true
+license = "MIT OR Apache-2.0"
 
 [dependencies]
 serde = { workspace = true }
@@ -14,5 +14,6 @@ thiserror = { workspace = true }
 chrono = { workspace = true }
 regex = { workspace = true }
 petgraph = { workspace = true }
+toml = "0.8"
 
 [dev-dependencies]