feat: consolidate web auth and add Effect v4 Project primitives

Auth:
- Add useWebAuth hook as the single web-facing auth interface with four
  states (loading/unauthenticated/authenticated/inconsistent)
- Normalize getCurrentUser to return {id: tokenIdentifier, name, email}
- Rename requireOwnerId to requireAuthUserId across all backend callers
- Set expectAuth:true on ConvexReactClient singleton
- Migrate _app, _auth, user-menu, use-personal-organization to useWebAuth
- Remove unused @code/auth/server export (zero callers confirmed)

Primitives:
- Add packages/primitives/src/project.ts with Effect v4 Project domain:
  URL normalization, six canonical context kinds, strict remote decoding,
  context write decisioning with revision tracking, and no-op detection
- Define PublicGit and ProjectStore replaceable ports
- Define ProjectApplication service orchestrating domain+ports with
  deterministic error mapping
- Add comprehensive test suite (28 tests) with in-memory store and fake
  PublicGit covering normalization, seeds, idempotency, tenant isolation,
  last-write-wins, and typed error mapping

packages/backend/convex/projectIssues.ts

@@ -3,7 +3,7 @@ import { ConvexError, v } from "convex/values";
 import type { Id } from "./_generated/dataModel";
 import { mutation, query } from "./_generated/server";
 import type { MutationCtx } from "./_generated/server";
-import { requireOwnerId } from "./authz";
+import { requireAuthUserId } from "./authz"
 
 const requireProjectOwner = async (
   ctx: MutationCtx,
@@ -24,7 +24,7 @@ export const create = mutation({
     title: v.string(),
   },
   handler: async (ctx, args) => {
-    const ownerId = await requireOwnerId(ctx);
+    const ownerId = await requireAuthUserId(ctx);
     await requireProjectOwner(ctx, args.projectId, ownerId);
     const title = args.title.trim();
     const body = args.body.trim();
@@ -81,7 +81,7 @@ export const create = mutation({
 export const begin = mutation({
   args: { issueId: v.id("projectIssues") },
   handler: async (ctx, args) => {
-    const ownerId = await requireOwnerId(ctx);
+    const ownerId = await requireAuthUserId(ctx);
     const issue = await ctx.db.get("projectIssues", args.issueId);
     if (!issue) {
       throw new ConvexError("Issue not found");
@@ -109,7 +109,7 @@ export const begin = mutation({
 export const markDispatchFailed = mutation({
   args: { error: v.string(), issueId: v.id("projectIssues") },
   handler: async (ctx, args) => {
-    const ownerId = await requireOwnerId(ctx);
+    const ownerId = await requireAuthUserId(ctx);
     const issue = await ctx.db.get("projectIssues", args.issueId);
     if (!issue) {
       throw new ConvexError("Issue not found");
@@ -133,7 +133,7 @@ export const markDispatchFailed = mutation({
 export const list = query({
   args: { projectId: v.id("projects") },
   handler: async (ctx, args) => {
-    const ownerId = await requireOwnerId(ctx);
+    const ownerId = await requireAuthUserId(ctx);
     const project = await ctx.db.get("projects", args.projectId);
     if (!project || project.ownerId !== ownerId) {
       return [];