v1.13.20-drop-legacy-cols: final phase of v1.13.0 strangler-fig

Removes the dual-write into messages.tool_calls / messages.tool_results JSON
columns and drops the columns. message_parts is now the only source of truth
for tool calls and tool results.

10 dual-write sites stripped (5 in tool-phase.ts, 2 in routes/skills.ts, 2 in
routes/messages.ts, 1 in routes/chats.ts fork-clone). The recon-driven grep
caught 2 sites beyond the original v1.13.2 roadmap inventory and an extra
fixture file (tool_cost_stats.test.ts) with a direct legacy-column INSERT.

messages_with_parts view rewritten to parts-only subselects (COALESCE
fallbacks gone). View runs via CREATE OR REPLACE so it lands before the
column DROPs in startup DDL — Postgres rejects column-drop on view-referenced
cols. v1.12.1 cleanup DO block (DROP CONSTRAINT messages_status_check /
messages_role_check) removed; those one-shots have done their work.

Adversarial review caught a runtime bug the green test suite missed: the
discard_stale endpoint (chats.ts) had a RETURNING ... tool_calls, tool_results
clause that would have crashed on every 60s-no-token-activity recovery in
production. Fixed by switching to two-step UPDATE returning id, then SELECT
from messages_with_parts so parts-synthesized fields keep flowing on the wire.

Message API type retains tool_calls? / tool_results? — the view synthesizes
those keys from parts so the wire shape is unchanged; frontend reads need no
update. Override on the original v1.13.2 plan, captured in the openspec
proposal.

339/339 server tests passing (including 7 DB-integration tests that applied
the schema migration to a live DB and ran the parts-only view end-to-end).
tsc + web build clean.

Pairs with v1.13.0-ai-sdk-v6 (introduced the dual-write) and v1.13.1-B (moved
the read path to messages_with_parts). Umbrella v1.13 tag ships on this same
commit, marking the strangler-fig closed.

CLAUDE.md picks up Sam's pre-existing edits documenting tag-naming and
CHANGELOG conventions — both already in use by v1.13.19 / v1.13.20.

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

apps/server/src/routes/chats.ts

@@ -296,13 +296,13 @@ export function registerChatRoutes(
         `;
         await tx`
           INSERT INTO messages (
-            session_id, chat_id, role, content, kind, tool_calls, tool_results,
+            session_id, chat_id, role, content, kind,
             status, tokens_used, ctx_used, ctx_max, started_at, finished_at,
             created_at, metadata
           )
           SELECT
             ${source.session_id}, ${chat!.id}, role, content, kind,
-            tool_calls, tool_results, status,
+            status,
             tokens_used, ctx_used, ctx_max, started_at, finished_at,
             clock_timestamp() + (
               ROW_NUMBER() OVER (ORDER BY created_at ASC, id ASC) * INTERVAL '1 microsecond'
@@ -385,21 +385,25 @@ export function registerChatRoutes(
         reply.code(409);
         return { error: 'message is not stale yet', age_seconds: msg.age_seconds };
       }
-      const updated = await sql<Message[]>`
+      const updated = await sql<{ id: string }[]>`
         UPDATE messages
         SET status = 'failed',
             content = COALESCE(content, ''),
             finished_at = clock_timestamp()
         WHERE id = ${msg.id} AND status = 'streaming'
-        RETURNING id, session_id, chat_id, role, content, kind, tool_calls, tool_results,
-                  status, last_seq, tokens_used, ctx_used, ctx_max, started_at, finished_at,
-                  created_at, metadata, summary, tail_start_id, compacted_at
+        RETURNING id
       `;
       if (updated.length === 0) {
         // Race: the row flipped out of 'streaming' between our SELECT and UPDATE.
         reply.code(409);
         return { error: 'message status changed mid-request' };
       }
+      // v1.13.20: re-fetch via messages_with_parts so the returned shape
+      // carries parts-synthesized tool_calls / tool_results. The dropped
+      // legacy columns can no longer be selected directly.
+      const refreshed = await sql<Message[]>`
+        SELECT * FROM messages_with_parts WHERE id = ${msg.id}
+      `;
       broker.publishUserFrame('default', {
         type: 'chat_status',
         chat_id: msg.chat_id,
@@ -411,7 +415,7 @@ export function registerChatRoutes(
         message_id: msg.id,
         chat_id: msg.chat_id,
       });
-      return updated[0];
+      return refreshed[0];
     }
   );