PAP-70: project icon infra + ProjectTile renderer + picker (PAP-68 part 3)

Adds the project icon system mirroring the agent icon pattern:

- shared: PROJECT_ICON_NAMES + ProjectIconName (default "folder", curated
  Lucide set), exported from index; tighten project validator icon field
  from loose string to z.enum(PROJECT_ICON_NAMES).
- ui: project-icons.ts (PROJECT_ICONS map + getProjectIcon defaulting to
  folder) and ProjectIconPicker (Popover + search + grid), mirroring the
  agent equivalents.
- ProjectTile gains an optional `icon` prop, rendering getProjectIcon(icon)
  instead of a hard-coded Folder (default unchanged). Color behavior intact.
- Pass icon={project.icon ?? null} at all three tile sites: Projects list,
  SidebarProjects, and the detail header (threaded through ColorPicker).
- Tests: ProjectTile renders chosen icon / falls back to folder for unknown.
- Backfill required Project.icon on test/storybook fixtures left un-updated
  by part 1, restoring a green UI typecheck.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/shared/src/constants.ts

@@ -124,6 +124,56 @@ export const AGENT_ICON_NAMES = [
 ] as const;
 export type AgentIconName = (typeof AGENT_ICON_NAMES)[number];
 
+/**
+ * Curated Lucide icon set for projects (PAP-68 part 3).
+ *
+ * The first entry, `"folder"`, is the default for any project without an
+ * explicit icon. The remaining entries reuse much of the agent icon set plus a
+ * handful of folder/structure icons that read well at small tile sizes.
+ */
+export const PROJECT_ICON_NAMES = [
+  "folder",
+  "rocket",
+  "code",
+  "terminal",
+  "database",
+  "globe",
+  "package",
+  "boxes",
+  "box",
+  "layers",
+  "briefcase",
+  "compass",
+  "target",
+  "flame",
+  "zap",
+  "star",
+  "bug",
+  "wrench",
+  "hammer",
+  "lightbulb",
+  "sparkles",
+  "shield",
+  "lock",
+  "search",
+  "cog",
+  "brain",
+  "cpu",
+  "git-branch",
+  "file-code",
+  "puzzle",
+  "gem",
+  "atom",
+  "heart",
+  "mail",
+  "message-square",
+  "crown",
+  "radar",
+  "telescope",
+  "hexagon",
+] as const;
+export type ProjectIconName = (typeof PROJECT_ICON_NAMES)[number];
+
 export const ISSUE_STATUSES = [
   "backlog",
   "todo",

packages/shared/src/index.ts

@@ -41,6 +41,7 @@ export {
   WORKSPACE_BRANCH_ROUTINE_VARIABLE,
   MODEL_PROFILE_KEYS,
   AGENT_ICON_NAMES,
+  PROJECT_ICON_NAMES,
   ISSUE_STATUSES,
   INBOX_MINE_ISSUE_STATUSES,
   INBOX_MINE_ISSUE_STATUS_FILTER,
@@ -169,6 +170,7 @@ export {
   type AgentRole,
   type ModelProfileKey,
   type AgentIconName,
+  type ProjectIconName,
   type IssueStatus,
   type IssuePriority,
   type IssueWorkMode,

packages/shared/src/validators/project.ts

@@ -1,5 +1,5 @@
 import { z } from "zod";
-import { PROJECT_STATUSES } from "../constants.js";
+import { PROJECT_STATUSES, PROJECT_ICON_NAMES } from "../constants.js";
 import { envConfigSchema } from "./secret.js";
 import { trustAuthorizationPolicySchema } from "./trust-policy.js";
 
@@ -107,9 +107,7 @@ const projectFields = {
   leadAgentId: z.string().uuid().optional().nullable(),
   targetDate: z.string().optional().nullable(),
   color: z.string().optional().nullable(),
-  // TODO(PAP-68 part 3): tighten to `z.enum(PROJECT_ICON_NAMES)` once the icon
-  // name enum lands. Loosely typed as a string until then.
-  icon: z.string().optional().nullable(),
+  icon: z.enum(PROJECT_ICON_NAMES).optional().nullable(),
   env: envConfigSchema.optional().nullable(),
   executionWorkspacePolicy: projectExecutionWorkspacePolicySchema.optional().nullable(),
   archivedAt: z.string().datetime().optional().nullable(),