fix: read_all_items must use deduplicated index, not raw CRDT entries

read_all_items was iterating all CRDT entries including stale duplicates
from earlier stage writes. A story written multiple times (backlog →
current → done) would appear in the output multiple times with different
stages, causing ghost entries in the pipeline status and backlog views.

Now iterates only the index (story_id → visible_index map) which
represents the latest-wins deduplicated view of each story.

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

server/Cargo.toml

@@ -42,7 +42,6 @@ sqlx = { workspace = true }
 wait-timeout = "0.2.1"
 bft-json-crdt = { path = "../crates/bft-json-crdt", default-features = false, features = ["bft"] }
 fastcrypto = "0.1.8"
-hex = "0.4"
 indexmap = { version = "2.2.6", features = ["serde"] }
 
 [target.'cfg(unix)'.dependencies]