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/services/__tests__/tool_cost_stats.test.ts

@@ -78,16 +78,18 @@ describeFn('tool_cost_stats view (v1.13.10)', () => {
       args: {},
     }));
     const created = opts.createdAt ?? new Date();
+    // v1.13.20: parts-only. messages.tool_calls column was dropped; the
+    // tool_cost_stats view reads through messages_with_parts which derives
+    // tool_calls from message_parts rows.
     const rows = await sql<{ id: string }[]>`
       INSERT INTO messages (
         session_id, chat_id, role, content, kind, status,
-        tool_calls, tokens_used, ctx_used,
+        tokens_used, ctx_used,
         metadata, created_at
       )
       VALUES (
         ${sessionId}, ${chatId}, 'assistant', '', 'message',
         ${opts.status ?? 'complete'},
-        ${sql.json(toolCalls as never)},
         ${opts.tokensUsed},
         ${opts.ctxUsed},
         ${opts.metadata ? sql.json(opts.metadata as never) : null},
@@ -95,7 +97,14 @@ describeFn('tool_cost_stats view (v1.13.10)', () => {
       )
       RETURNING id
     `;
-    return rows[0]!.id;
+    const messageId = rows[0]!.id;
+    for (let i = 0; i < toolCalls.length; i++) {
+      await sql`
+        INSERT INTO message_parts (message_id, sequence, kind, payload)
+        VALUES (${messageId}, ${i}, 'tool_call', ${sql.json(toolCalls[i] as never)})
+      `;
+    }
+    return messageId;
   }
 
   it('returns empty when no tool calls exist for a tool name', async () => {
@@ -197,18 +206,17 @@ describeFn('tool_cost_stats view (v1.13.10)', () => {
 
   it('reads tool_calls via messages_with_parts (parts-authoritative)', async () => {
     const t = tname('parts');
-    // Insert an assistant row with messages.tool_calls=NULL but a
-    // message_parts row carrying the tool_call. The view reads via
-    // messages_with_parts, which COALESCEs the parts table over the legacy
-    // column — so this row should still aggregate.
+    // v1.13.20: post-column-drop the only source for tool_calls is
+    // message_parts. This test asserts the same path the view always took
+    // (parts-derived), now that the legacy column COALESCE fallback is gone.
     const rows = await sql<{ id: string }[]>`
       INSERT INTO messages (
         session_id, chat_id, role, content, kind, status,
-        tool_calls, tokens_used, ctx_used
+        tokens_used, ctx_used
       )
       VALUES (
         ${sessionId}, ${chatId}, 'assistant', '', 'message', 'complete',
-        NULL, 200, 5000
+        200, 5000
       )
       RETURNING id
     `;