Add Video Projects schema and workflow engine core (tasks #31, #32)

Foundational layer for the YouTube Content Creation System project,
built as a fully independent domain per the earlier decision (task
#47) — no foreign keys into the existing projects/tasks/ideas tables.

Schema: video_projects, workflow_steps, assets, ai_providers,
workflow_templates (named to avoid colliding with the existing
Post-templates `templates` table).

WorkflowEngine (app/Support/VideoWorkflow/) drives a project's step
sequence: start/startFromTemplate, currentStep, completeStep (with
optional approval gating), approveStep/rejectStep, failStep/retryStep,
skipStep. It only manages state transitions — actual step execution
(AI calls, rendering, etc.) is out of scope here (tasks #33+).

Also fixes four Publisher classes (WordPress/Reddit/Twitter/LinkedIn)
that were missing a `use App\Models\SocialAccount;` import after an
earlier interface change, which broke the entire test suite at
bootstrap; and PostFactory, which still set the now-removed
`social_account_id` column instead of the SocialAccount pivot.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/Models/AiProvider.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+class AiProvider extends Model
+{
+    use HasFactory;
+
+    public const PROVIDERS = ['openai', 'stability_ai', 'elevenlabs', 'other'];
+
+    protected $fillable = [
+        'name',
+        'provider',
+        'api_key',
+        'config',
+        'is_active',
+    ];
+
+    protected $casts = [
+        'config' => 'array',
+        'is_active' => 'boolean',
+    ];
+}

app/Models/Asset.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class Asset extends Model
+{
+    use HasFactory;
+
+    public const TYPES = ['script', 'image', 'video', 'audio', 'other'];
+
+    protected $fillable = [
+        'video_project_id',
+        'workflow_step_id',
+        'type',
+        'disk_path',
+        'mime_type',
+        'size_bytes',
+        'version',
+        'metadata',
+    ];
+
+    protected $casts = [
+        'metadata' => 'array',
+    ];
+
+    public function videoProject(): BelongsTo
+    {
+        return $this->belongsTo(VideoProject::class);
+    }
+
+    public function workflowStep(): BelongsTo
+    {
+        return $this->belongsTo(WorkflowStep::class);
+    }
+}

app/Models/VideoProject.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+use Illuminate\Database\Eloquent\SoftDeletes;
+
+class VideoProject extends Model
+{
+    use HasFactory, SoftDeletes;
+
+    public const STATUSES = ['draft', 'in_progress', 'completed', 'archived'];
+
+    protected $fillable = [
+        'title',
+        'description',
+        'status',
+        'workflow_template_id',
+    ];
+
+    public function workflowTemplate(): BelongsTo
+    {
+        return $this->belongsTo(WorkflowTemplate::class);
+    }
+
+    public function steps(): HasMany
+    {
+        return $this->hasMany(WorkflowStep::class)->orderBy('order');
+    }
+
+    public function assets(): HasMany
+    {
+        return $this->hasMany(Asset::class);
+    }
+}

app/Models/WorkflowStep.php

@@ -0,0 +1,62 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+class WorkflowStep extends Model
+{
+    use HasFactory;
+
+    // Mirrors the content-generation modules in the YouTube Content
+    // Creation System project (script through publish).
+    public const TYPES = [
+        'script_generation',
+        'tts_voiceover',
+        'storyboard',
+        'video_generation',
+        'video_editing',
+        'thumbnail_generation',
+        'metadata_generation',
+        'youtube_publish',
+    ];
+
+    public const STATUSES = [
+        'pending', 'in_progress', 'awaiting_approval',
+        'completed', 'rejected', 'failed', 'skipped',
+    ];
+
+    protected $fillable = [
+        'video_project_id',
+        'type',
+        'order',
+        'status',
+        'requires_approval',
+        'input',
+        'output',
+        'error',
+        'started_at',
+        'completed_at',
+    ];
+
+    protected $casts = [
+        'requires_approval' => 'boolean',
+        'input' => 'array',
+        'output' => 'array',
+        'started_at' => 'datetime',
+        'completed_at' => 'datetime',
+    ];
+
+    public function videoProject(): BelongsTo
+    {
+        return $this->belongsTo(VideoProject::class);
+    }
+
+    public function assets(): HasMany
+    {
+        return $this->hasMany(Asset::class);
+    }
+}

app/Models/WorkflowTemplate.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+class WorkflowTemplate extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'name',
+        'description',
+        'steps',
+    ];
+
+    protected $casts = [
+        'steps' => 'array',
+    ];
+
+    public function videoProjects(): HasMany
+    {
+        return $this->hasMany(VideoProject::class);
+    }
+}

app/Support/Publishing/LinkedInPublisher.php

@@ -3,6 +3,7 @@
 namespace App\Support\Publishing;
 
 use App\Models\Post;
+use App\Models\SocialAccount;
 use Illuminate\Support\Facades\Log;
 use Illuminate\Support\Facades\Process;
 

app/Support/Publishing/RedditPublisher.php

@@ -3,6 +3,7 @@
 namespace App\Support\Publishing;
 
 use App\Models\Post;
+use App\Models\SocialAccount;
 use Illuminate\Support\Facades\Log;
 use Illuminate\Support\Facades\Process;
 

app/Support/Publishing/TwitterPublisher.php

@@ -3,6 +3,7 @@
 namespace App\Support\Publishing;
 
 use App\Models\Post;
+use App\Models\SocialAccount;
 use Illuminate\Support\Facades\Log;
 use Illuminate\Support\Facades\Process;
 

app/Support/Publishing/WordPressPublisher.php

@@ -4,6 +4,7 @@ namespace App\Support\Publishing;
 
 use App\Models\Post;
 use App\Models\Site;
+use App\Models\SocialAccount;
 use Illuminate\Http\Client\ConnectionException;
 use Illuminate\Support\Facades\Http;
 

app/Support/VideoWorkflow/WorkflowEngine.php

@@ -0,0 +1,191 @@
+<?php
+
+namespace App\Support\VideoWorkflow;
+
+use App\Models\VideoProject;
+use App\Models\WorkflowStep;
+use App\Models\WorkflowTemplate;
+
+/**
+ * Drives a VideoProject's pipeline: creates its step sequence and manages
+ * step state transitions (execution, approval, failure, retry).
+ *
+ * Steps run strictly in `order`. Each step is one of:
+ *   pending -> in_progress -> awaiting_approval -> completed
+ *                          \-> completed (skips approval if not required)
+ *                          \-> failed -> in_progress (retry)
+ *              awaiting_approval -> rejected -> in_progress (retry)
+ *   pending | in_progress -> skipped
+ *
+ * This class only manages state — it doesn't know how to actually generate
+ * a script, render video, etc. Whatever does that work (a future AI
+ * provider integration, a human, an Artisan command) calls completeStep()/
+ * failStep() to report the result.
+ */
+class WorkflowEngine
+{
+    /**
+     * Create the step sequence for a project and activate the first one.
+     *
+     * @param  array<int, array{type: string, requires_approval?: bool}>  $steps
+     */
+    public function start(VideoProject $project, array $steps): WorkflowStep
+    {
+        if ($project->steps()->exists()) {
+            throw new WorkflowTransitionException("Video project {$project->id} already has workflow steps.");
+        }
+
+        if (empty($steps)) {
+            throw new WorkflowTransitionException('Cannot start a workflow with no steps.');
+        }
+
+        foreach (array_values($steps) as $order => $step) {
+            $project->steps()->create([
+                'type' => $step['type'],
+                'order' => $order,
+                'status' => 'pending',
+                'requires_approval' => $step['requires_approval'] ?? false,
+            ]);
+        }
+
+        $project->update(['status' => 'in_progress']);
+
+        $first = $project->steps()->orderBy('order')->firstOrFail();
+
+        return $this->activate($first);
+    }
+
+    public function startFromTemplate(VideoProject $project, WorkflowTemplate $template): WorkflowStep
+    {
+        $project->update(['workflow_template_id' => $template->id]);
+
+        return $this->start($project, $template->steps);
+    }
+
+    /**
+     * The step currently blocking progress — pending, running, awaiting
+     * approval, or stuck on failure/rejection. Null once every step is
+     * completed or skipped.
+     */
+    public function currentStep(VideoProject $project): ?WorkflowStep
+    {
+        return $project->steps()
+            ->whereNotIn('status', ['completed', 'skipped'])
+            ->orderBy('order')
+            ->first();
+    }
+
+    public function completeStep(WorkflowStep $step, array $output = []): WorkflowStep
+    {
+        $this->assertStatus($step, 'in_progress');
+
+        $step->update([
+            'output' => $output,
+            'error' => null,
+            'completed_at' => now(),
+            'status' => $step->requires_approval ? 'awaiting_approval' : 'completed',
+        ]);
+
+        if ($step->status === 'completed') {
+            $this->activateNext($step);
+        }
+
+        return $step->fresh();
+    }
+
+    public function approveStep(WorkflowStep $step): WorkflowStep
+    {
+        $this->assertStatus($step, 'awaiting_approval');
+
+        $step->update(['status' => 'completed']);
+
+        $this->activateNext($step);
+
+        return $step->fresh();
+    }
+
+    /**
+     * Rejecting does not advance the pipeline — it stays blocked on this
+     * step until retryStep() is called.
+     */
+    public function rejectStep(WorkflowStep $step, ?string $reason = null): WorkflowStep
+    {
+        $this->assertStatus($step, 'awaiting_approval');
+
+        $step->update(['status' => 'rejected', 'error' => $reason]);
+
+        return $step->fresh();
+    }
+
+    public function failStep(WorkflowStep $step, string $error): WorkflowStep
+    {
+        $this->assertStatus($step, 'in_progress');
+
+        $step->update(['status' => 'failed', 'error' => $error]);
+
+        return $step->fresh();
+    }
+
+    public function retryStep(WorkflowStep $step): WorkflowStep
+    {
+        if (! in_array($step->status, ['failed', 'rejected'], true)) {
+            throw new WorkflowTransitionException("Step {$step->id} can only be retried from failed or rejected, currently '{$step->status}'.");
+        }
+
+        $step->update([
+            'status' => 'in_progress',
+            'error' => null,
+            'output' => null,
+            'started_at' => now(),
+            'completed_at' => null,
+        ]);
+
+        return $step->fresh();
+    }
+
+    public function skipStep(WorkflowStep $step): WorkflowStep
+    {
+        if (! in_array($step->status, ['pending', 'in_progress'], true)) {
+            throw new WorkflowTransitionException("Step {$step->id} can only be skipped from pending or in_progress, currently '{$step->status}'.");
+        }
+
+        $step->update(['status' => 'skipped', 'completed_at' => now()]);
+
+        $this->activateNext($step);
+
+        return $step->fresh();
+    }
+
+    private function activate(WorkflowStep $step): WorkflowStep
+    {
+        $step->update(['status' => 'in_progress', 'started_at' => now()]);
+
+        return $step->fresh();
+    }
+
+    private function activateNext(WorkflowStep $justFinished): void
+    {
+        $project = $justFinished->videoProject;
+
+        $next = $project->steps()
+            ->where('order', '>', $justFinished->order)
+            ->whereNotIn('status', ['completed', 'skipped'])
+            ->orderBy('order')
+            ->first();
+
+        if ($next) {
+            $this->activate($next);
+
+            return;
+        }
+
+        $project->update(['status' => 'completed']);
+    }
+
+    private function assertStatus(WorkflowStep $step, string $expected): void
+    {
+        if ($step->status !== $expected) {
+            throw new WorkflowTransitionException("Step {$step->id} must be '{$expected}' for this transition, currently '{$step->status}'.");
+        }
+    }
+}

app/Support/VideoWorkflow/WorkflowTransitionException.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace App\Support\VideoWorkflow;
+
+use RuntimeException;
+
+class WorkflowTransitionException extends RuntimeException {}