refactor(views): unify view DDL into the single schema-diff path

The schema-diff now owns ALL view DDL for every dialect, replacing the
parallel computeProjectionMigrations / source-aware-diff emitter. One
generator (emitViewDdl via buildProjectionViews) produces every CREATE
VIEW; the diff produces create/drop/replace plus a dependency-recreate
pass; each dialect renderer emits it.

- migrate-ts: port view rendering into the sqlite/d1 emitter, drop the
  postgres-only guard; add diff Pass 2c (drop+recreate a view around a
  column-altering change to a table it reads), driven by a new
  ViewDescriptor.dependsOn; sqlite STAGE_ORDER drop-view=0 (before the
  recreate-and-copy, mirroring postgres); introspectD1 reads view bodies.
- codegen-ts: buildProjectionViews is the single expected-view source
  (name/body/schema/dependsOn); emitViewDdl gains bodyOnly; resolve JOIN
  FK/PK to physical columns (naming strategy + @column) instead of a
  hardcoded snake_case guess; quote identifiers that need it so literal/
  kebab columns survive postgres case-folding.
- cli: emit all diff changes (tables + views) through one path; delete
  computeProjectionMigrations + the view-diff stack.

Deletes source-aware-diff, view-diff, view-ddl-{postgres,sqlite},
expected-views, projection-migrations and their tests; removes the
corresponding migrate-ts barrel exports.

Validated: full unit suites green, postgres persistence-conformance
(incl. a new recreate-view-on-column-type-change scenario), and a live
from-empty platform migrate emitting exactly one correct CREATE VIEW.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: dmealing

fixtures/persistence-conformance/migrations/recreate-view-on-column-type-change.yaml

@@ -0,0 +1,27 @@
+name: recreate-view-on-column-type-change
+description: |
+  A view (projection) reads programs.title. Widening title VARCHAR(200) → VARCHAR(500)
+  is a column-type change postgres REFUSES while a view depends on the column
+  ("cannot alter type of a column used by a view"). The schema-diff's dependency
+  pass (Pass 2c) must drop the view BEFORE the ALTER and recreate it AFTER, so the
+  whole migration applies cleanly and the view still returns rows. This pins the one
+  emission path owning view DDL — no separate view-migration emitter.
+
+seed-metadata: ./states/program-view-v1/
+seed-data: |
+  INSERT INTO "programs" ("id", "title") VALUES (1, 'Foundations'), (2, 'Strength');
+
+target-metadata: ./states/program-view-v2/
+
+expect:
+  blocked: []
+  up-contains:
+    - 'DROP VIEW'
+    - 'v_program'
+    - 'ALTER TABLE "programs"'
+    - 'CREATE VIEW'
+  apply-up-then-query:
+    sql: SELECT "id", "title" FROM "v_program" ORDER BY "id"
+    rows:
+      - { id: "1", title: "Foundations" }
+      - { id: "2", title: "Strength" }

fixtures/persistence-conformance/migrations/states/program-view-v1/meta.json

@@ -0,0 +1,25 @@
+{
+  "metadata.root": {
+    "package": "fitness",
+    "children": [
+      { "object.entity": {
+        "name": "Program",
+        "children": [
+          { "source.rdb": { "@table": "programs" } },
+          { "field.long":   { "name": "id" } },
+          { "field.string": { "name": "title", "@required": true, "@maxLength": 200 } },
+          { "identity.primary": { "name": "id", "@fields": "id", "@generation": "increment" } }
+        ]
+      }},
+      { "object.projection": {
+        "name": "ProgramView",
+        "children": [
+          { "source.rdb": { "@kind": "view", "@table": "v_program" } },
+          { "field.long":   { "name": "id",    "extends": "fitness::Program.id" } },
+          { "field.string": { "name": "title", "children": [ { "origin.passthrough": { "@from": "fitness::Program.title" } } ] } },
+          { "identity.primary": { "name": "id", "extends": "fitness::Program.id" } }
+        ]
+      }}
+    ]
+  }
+}

fixtures/persistence-conformance/migrations/states/program-view-v2/meta.json

@@ -0,0 +1,25 @@
+{
+  "metadata.root": {
+    "package": "fitness",
+    "children": [
+      { "object.entity": {
+        "name": "Program",
+        "children": [
+          { "source.rdb": { "@table": "programs" } },
+          { "field.long":   { "name": "id" } },
+          { "field.string": { "name": "title", "@required": true, "@maxLength": 500 } },
+          { "identity.primary": { "name": "id", "@fields": "id", "@generation": "increment" } }
+        ]
+      }},
+      { "object.projection": {
+        "name": "ProgramView",
+        "children": [
+          { "source.rdb": { "@kind": "view", "@table": "v_program" } },
+          { "field.long":   { "name": "id",    "extends": "fitness::Program.id" } },
+          { "field.string": { "name": "title", "children": [ { "origin.passthrough": { "@from": "fitness::Program.title" } } ] } },
+          { "identity.primary": { "name": "id", "extends": "fitness::Program.id" } }
+        ]
+      }}
+    ]
+  }
+}