docs: mark SP4 partial shipped (claim drawer); tick all plan checkboxes

README.md

@@ -123,7 +123,7 @@ backup API).
 
 ## Roadmap
 
-Sub-projects 2 and 3 are **shipped**. Next up:
+Sub-projects 2, 3, and the first half of 4 are **shipped**. Next up:
 
 - **Sub-project 3 (shipped) — More 837P/835 features.**
   - **837P validation rules:** R034 enforces `REF*G1` on frequency-code
@@ -142,10 +142,21 @@ Sub-projects 2 and 3 are **shipped**. Next up:
     builds a 270 from a JSON payload (subscriber, provider, payer,
     service type); `POST /api/eligibility/parse-271` ingests the
     response and returns structured `coverage_benefits`.
-- **Sub-project 4 — Frontend features.** Per-claim detail drawer, batch
-  diff view, real-time streaming of NDJSON GET responses, advanced
-  filters (date range, multi-status, saved filter sets), keyboard-driven
-  navigation.
+- **Sub-project 4 (partially shipped) — Frontend features.**
+  - **Per-claim detail drawer (shipped):** click any row on the Claims
+    page to open a side-panel drawer with the full claim context —
+    state + amount header, validation panel, service lines, diagnoses,
+    parties (billing provider, subscriber, payer), raw X12 segments,
+    matched remittance summary, and a vertical state-history timeline.
+    URL is synced (`?claim=...`) so links and back-button restore the
+    drawer. Keyboard nav: `j`/`k` move between claims, `esc` closes,
+    `?` opens the cheatsheet overlay. Skeleton + error + not-found
+    (404) states are all distinct. Powered by a new backend endpoint
+    `GET /api/claims/{claim_id}` that returns the full drawer payload
+    in a single round-trip.
+  - **Remaining SP4:** batch diff view, real-time streaming of NDJSON
+    GET responses, advanced filters (date range, multi-status, saved
+    filter sets).
 
 ### SP3 endpoints
 
@@ -162,6 +173,17 @@ Sub-projects 2 and 3 are **shipped**. Next up:
 The UI gains a new **Acks** page (sidebar entry) that lists persisted
 ACKs and lets you download the regenerated 999 text.
 
+### SP4 endpoints (claim drawer)
+
+- `GET /api/claims/{claim_id}` — full claim context for the drawer
+  payload: header fields, diagnoses, service lines, parties
+  (billing provider / subscriber / payer), validation result, raw
+  X12 segments, matched remittance summary (or `null`), and the
+  claim's state history (ordered newest-first). 404 with a structured
+  `{ "error": "Not found", "detail": "Claim {id} not found" }` body
+  when the claim doesn't exist — distinct from a transient fetch
+  failure so the UI can render a dedicated not-found state.
+
 ## License
 
 No license file yet; this is internal-use software. Add a `LICENSE` file