FRE-594: Implement revision tracking and version history system

Add complete revision tracking system for scripts with:
- Database schema for revisions and revision_changes tables
- Diff engine with color-coded change types (addition/deletion/modification)
- tRPC router with 14 endpoints (create/list/compare/rollback/branch/merge)
- SolidJS components: RevisionTimeline, DiffViewer, RevisionReview
- Unit tests for diff engine and router

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/db/schema/revisions.ts

@@ -0,0 +1,77 @@
+import { sqliteTable, text, integer, index } from "drizzle-orm/sqlite-core";
+import { scripts } from "./scripts";
+import { users } from "./users";
+
+export const revisions = sqliteTable(
+  "revisions",
+  {
+    id: integer("id").primaryKey({ autoIncrement: true }),
+    scriptId: integer("script_id")
+      .notNull()
+      .references(() => scripts.id),
+    versionNumber: integer("version_number").notNull(),
+    branchName: text("branch_name").notNull().default("main"),
+    parentRevisionId: integer("parent_revision_id"),
+    title: text("title").notNull(),
+    summary: text("summary"),
+    content: text("content").notNull(),
+    authorId: integer("author_id")
+      .notNull()
+      .references(() => users.id),
+    status: text("status", {
+      enum: ["draft", "pending_review", "accepted", "rejected"],
+    })
+      .notNull()
+      .default("draft"),
+    reviewedById: integer("reviewed_by_id").references(() => users.id),
+    reviewedAt: integer("reviewed_at", { mode: "timestamp" }),
+    createdAt: integer("created_at", { mode: "timestamp" })
+      .notNull()
+      .$defaultFn(() => new Date()),
+    updatedAt: integer("updated_at", { mode: "timestamp" })
+      .notNull()
+      .$defaultFn(() => new Date()),
+  },
+  (table) => ({
+    scriptVersionIdx: index("revisions_script_version_idx").on(
+      table.scriptId,
+      table.versionNumber
+    ),
+    scriptBranchIdx: index("revisions_script_branch_idx").on(
+      table.scriptId,
+      table.branchName
+    ),
+    authorIdx: index("revisions_author_idx").on(table.authorId),
+  })
+);
+
+export const revisionChanges = sqliteTable(
+  "revision_changes",
+  {
+    id: integer("id").primaryKey({ autoIncrement: true }),
+    revisionId: integer("revision_id")
+      .notNull()
+      .references(() => revisions.id),
+    changeType: text("change_type", {
+      enum: ["addition", "deletion", "modification"],
+    }).notNull(),
+    elementType: text("element_type"),
+    oldContent: text("old_content"),
+    newContent: text("new_content"),
+    sceneNumber: integer("scene_number"),
+    lineNumber: integer("line_number"),
+    pageNumber: integer("page_number"),
+    createdAt: integer("created_at", { mode: "timestamp" })
+      .notNull()
+      .$defaultFn(() => new Date()),
+  },
+  (table) => ({
+    revisionIdx: index("revision_changes_revision_idx").on(table.revisionId),
+    changeTypeIdx: index("revision_changes_type_idx").on(table.changeType),
+  })
+);
+
+export type Revision = typeof revisions.$inferSelect;
+export type NewRevision = typeof revisions.$inferInsert;
+export type RevisionChange = typeof revisionChanges.$inferSelect;
+export type NewRevisionChange = typeof revisionChanges.$inferInsert;