wip(929): stage 1 — migrate chat/commands/* off yaml_legacy

Each chat command that previously read parse_front_matter for story
metadata (name, agent, depends_on, blocked, retry_count, merge_failure,
qa_mode) now reads from the typed CRDT API:

- WorkItem (via crdt_state::read_item) for pipeline-item registers.
- MergeJobView (via crdt_state::read_merge_job) for the merge failure
  detail text, which has its own LWW-map CRDT entry.

Files migrated: depends.rs, freeze.rs, move_story.rs, overview.rs,
status/render.rs, triage.rs, unblock.rs, unreleased.rs.

unblock.rs: also removes the legacy front-matter cleanup branch that
fired when the typed Blocked→Coding transition failed. Post-929 there
is no YAML on disk to clean; the fallback now just resets retry_count
in the CRDT.

triage.rs: drops the YAML-only `review_hold` and `coverage_baseline`
fields from the dump. These have no CRDT register and were never
load-bearing on the triage output; if needed later, add a CRDT register
and surface it back.

Tests:
- The three status/render merge-failure rendering tests now seed a
  MergeJob CRDT entry via write_merge_job instead of writing YAML.
- The unblock test that asserted YAML cleanup on disk is now an assertion
  on the CRDT registers (blocked=false, retry_count=0). Also re-seeded
  in `2_blocked` stage so the typed Blocked → Coding transition actually
  fires (not the fallback path).

All 2855 tests pass; fmt clean; clippy clean.

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

server/src/chat/commands/unreleased.rs

@@ -140,55 +140,13 @@ fn slug_to_name(slug: &str) -> String {
     words.join(" ")
 }
 
-/// Find the human-readable name of a story by searching content store then filesystem.
-fn find_story_name(root: &std::path::Path, num_str: &str) -> Option<String> {
-    // Try content store first.
-    for id in crate::db::all_content_ids() {
-        let file_num = id.split('_').next().unwrap_or("");
-        if file_num == num_str
-            && let Some(c) = crate::db::read_content(&id)
-        {
-            return crate::db::yaml_legacy::parse_front_matter(&c)
-                .ok()
-                .and_then(|m| m.name);
-        }
-    }
-
-    // Fallback: filesystem scan.
-    const STAGES: &[&str] = &[
-        "1_backlog",
-        "2_current",
-        "3_qa",
-        "4_merge",
-        "5_done",
-        "6_archived",
-    ];
-    for stage in STAGES {
-        let dir = root.join(".huskies").join("work").join(stage);
-        if !dir.exists() {
-            continue;
-        }
-        if let Ok(entries) = std::fs::read_dir(&dir) {
-            for entry in entries.flatten() {
-                let path = entry.path();
-                if path.extension().and_then(|e| e.to_str()) != Some("md") {
-                    continue;
-                }
-                if let Some(stem) = path.file_stem().and_then(|s| s.to_str()) {
-                    let file_num = stem
-                        .split('_')
-                        .next()
-                        .filter(|s| !s.is_empty() && s.chars().all(|c| c.is_ascii_digit()))
-                        .unwrap_or("");
-                    if file_num == num_str {
-                        return std::fs::read_to_string(&path).ok().and_then(|c| {
-                            crate::db::yaml_legacy::parse_front_matter(&c)
-                                .ok()
-                                .and_then(|m| m.name)
-                        });
-                    }
-                }
-            }
+/// Find the human-readable name of a story from the CRDT (story 929 —
+/// CRDT is the sole source of story metadata).
+fn find_story_name(_root: &std::path::Path, num_str: &str) -> Option<String> {
+    let items = crate::crdt_state::read_all_items()?;
+    for item in items {
+        if item.story_id().split('_').next().unwrap_or("") == num_str {
+            return item.name().map(str::to_string);
         }
     }
     None