refactor(merge_insert): adapt insertIntoPksTableAndGetPk for Rust/C pks schema (TASK-149)

- Unpack pk_blob into individual PK column values using codec.unpack
- Build dynamic INSERT: INSERT INTO pks (__crsql_key, col1, col2) VALUES (NULL, ?, ?)
- Bind unpacked values in PK order
- Return auto-generated __crsql_key via last_insert_rowid()
- Remove base_rowid parameter from function signature
- Update call sites in changes_vtab.zig to use new signature
- Fix line 1744 to call insertOrUpdateColumn (was missing insertIntoBaseTable)
- Mark TableMergeStmts.sql_insert_pks as DEPRECATED (old schema)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

Author: subtleGradient

.tasks/active/TASK-149-refactor-insertIntoPksTableAndGetPk.md

@@ -31,6 +31,8 @@ Triggering issue:
   - `insertIntoPksTable()` (line ~658)
   - `insertIntoPksTableAndGetPk()` (line ~671)
   - `TableMergeStmts.sql_insert_pks` buffer and statement (line ~135)
+- `zig/src/changes_vtab.zig`:
+  - Remove base_rowid parameter from insertIntoPksTableAndGetPk calls (lines 1713, 1751)
 
 ## Acceptance Criteria
 1. `insertIntoPksTableAndGetPk()` must:
@@ -64,6 +66,9 @@ Triggering issue:
 ## Progress Log
 - 2025-12-21: Created from TASK-147 refactoring work. Compound PK bug fixed, findPkFromBlob refactored, this is next critical blocker.
 - 2025-12-21 14:30: Starting implementation. Reading existing code to understand the pattern from findPkFromBlob refactor.
+- 2025-12-21 14:35: Analyzed findPkFromBlob pattern. Now implementing new schema support with codec.unpack + dynamic INSERT.
+- 2025-12-21 14:45: Refactored insertIntoPksTableAndGetPk in merge_insert.zig - unpacks blob, builds dynamic INSERT, returns last_insert_rowid. Now fixing call sites in changes_vtab.zig.
+- 2025-12-21 15:00: Fixed call sites in changes_vtab.zig - removed base_rowid parameters from lines 1713, 1751. Fixed line 1744 to call insertOrUpdateColumn instead of missing insertIntoBaseTable function. Ready to build and test.
 
 ## Completion Notes
 (Empty until done.)

zig/src/changes_vtab.zig

@@ -1710,7 +1710,7 @@ fn changesUpdate(
                 };
 
                 // Insert into __crsql_pks table and get the pk (auto-increment key)
-                const pks_pk = merge_insert.insertIntoPksTableAndGetPk(api_db, table_slice, base_rowid, pk_ptr, @intCast(pk_len)) catch {
+                const pks_pk = merge_insert.insertIntoPksTableAndGetPk(api_db, table_slice, pk_ptr, @intCast(pk_len)) catch {
                     log.debug("changesUpdate: insertIntoPksTableAndGetPk for PK-only failed", .{});
                     return vtab.SQLITE_ERROR;
                 };
@@ -1741,14 +1741,14 @@ fn changesUpdate(
             const insert_value = toApiValue(argv[5]);
 
             // Step 1a: Insert into base table (returns the base table rowid)
-            const base_rowid = merge_insert.insertIntoBaseTable(api_db, table_slice, cid_slice, insert_value, pk_ptr, @intCast(pk_len)) catch {
-                log.debug("changesUpdate: insertIntoBaseTable failed", .{});
+            merge_insert.insertOrUpdateColumn(api_db, table_slice, cid_slice, insert_value, pk_ptr, @intCast(pk_len)) catch {
+                log.debug("changesUpdate: insertOrUpdateColumn failed", .{});
                 return vtab.SQLITE_ERROR;
             };
 
             // Step 1b: Insert into __crsql_pks table and get the pk (auto-increment key)
             // The pk is what we use for clock table entries, NOT the base table rowid
-            const pks_pk = merge_insert.insertIntoPksTableAndGetPk(api_db, table_slice, base_rowid, pk_ptr, @intCast(pk_len)) catch {
+            const pks_pk = merge_insert.insertIntoPksTableAndGetPk(api_db, table_slice, pk_ptr, @intCast(pk_len)) catch {
                 log.debug("changesUpdate: insertIntoPksTableAndGetPk failed", .{});
                 return vtab.SQLITE_ERROR;
             };