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/inference/tool-phase.ts

@@ -110,7 +110,6 @@ export async function executeToolPhase(
     UPDATE messages
     SET content = ${content},
         status = 'complete',
-        tool_calls = ${ctx.sql.json(toolCalls as never)},
         tokens_used = ${completionTokens},
         ctx_used = ${promptTokens},
         ctx_max = ${nCtx},
@@ -118,15 +117,11 @@ export async function executeToolPhase(
     WHERE id = ${assistantMessageId}
     RETURNING tokens_used, ctx_used, ctx_max, finished_at
   `;
-  // v1.13.0: dual-write to message_parts. v1.13.1-B made parts authoritative
-  // for reads via the messages_with_parts view; the JSON column write above
-  // remains for v1.13.1 fallback compatibility (dropped in v1.13.2).
+  // v1.13.20: message_parts is the sole source of truth for tool_calls.
+  // Legacy messages.tool_calls column was dropped; reads route through the
+  // messages_with_parts view.
   // v1.13.1-C: include result.reasoning so models with separate reasoning
   // channels (qwen3.6) get a kind='reasoning' part at sequence 0.
-  // TODO(v1.13.1): wrap the UPDATE above and this insertParts in a single
-  // sql.begin before flipping read authority to message_parts. Without the
-  // transaction, a crash between the two leaves an orphan message that
-  // becomes invisible in the parts-authoritative read path.
   await insertParts(
     ctx.sql,
     partsFromAssistantMessage({
@@ -192,16 +187,9 @@ export async function executeToolPhase(
       if (tc.name === 'ask_user_input') {
         pausingForUserInput = true;
         const sentinel = { tool_call_id: tc.id, output: null, truncated: false };
-        await ctx.sql`
-          UPDATE messages
-          SET tool_results = ${ctx.sql.json(sentinel as never)}
-          WHERE id = ${toolMessageId}
-        `;
-        // v1.13.0: mirror the pending sentinel into message_parts. The
-        // answer-endpoint UPDATE later (messages.ts:576) will delete and
-        // re-insert this part when the user submits their answer.
-        // TODO(v1.13.1): wrap the INSERT + UPDATE + insertParts triple in
-        // a per-iteration sql.begin before flipping read authority.
+        // v1.13.20: parts-only. The answer-endpoint UPDATE later
+        // (messages.ts) will delete and re-insert this part when the user
+        // submits their answer.
         await insertParts(
           ctx.sql,
           partsFromToolMessage({ tool_results: sentinel }).map((p) => ({
@@ -234,11 +222,7 @@ export async function executeToolPhase(
             output: `denied: ${resolution.reason}`,
             truncated: false,
           };
-          await ctx.sql`
-            UPDATE messages
-            SET tool_results = ${ctx.sql.json(stored as never)}
-            WHERE id = ${toolMessageId}
-          `;
+          // v1.13.20: parts-only write.
           await insertParts(
             ctx.sql,
             partsFromToolMessage({ tool_results: stored }).map((p) => ({
@@ -261,11 +245,7 @@ export async function executeToolPhase(
         // (state may have changed in the meantime) so we don't stash it here.
         pausingForUserInput = true;
         const sentinel = { tool_call_id: tc.id, output: null, truncated: false };
-        await ctx.sql`
-          UPDATE messages
-          SET tool_results = ${ctx.sql.json(sentinel as never)}
-          WHERE id = ${toolMessageId}
-        `;
+        // v1.13.20: parts-only write.
         await insertParts(
           ctx.sql,
           partsFromToolMessage({ tool_results: sentinel }).map((p) => ({
@@ -285,14 +265,7 @@ export async function executeToolPhase(
         truncated: tres.truncated,
         ...(tres.error ? { error: tres.error } : {}),
       };
-      await ctx.sql`
-        UPDATE messages
-        SET tool_results = ${ctx.sql.json(stored as never)}
-        WHERE id = ${toolMessageId}
-      `;
-      // v1.13.0: dual-write the tool_result part.
-      // TODO(v1.13.1): wrap the INSERT + UPDATE + insertParts triple in a
-      // per-iteration sql.begin before flipping read authority.
+      // v1.13.20: parts-only write. Reads route through messages_with_parts.
       await insertParts(
         ctx.sql,
         partsFromToolMessage({ tool_results: stored }).map((p) => ({