fix: correct agent modes from 'all' to 'subagent'

These agents are invoked by other agents (orchestrator), not directly by user:
- history-miner: invoked by orchestrator during [planned] phase
- system-analyst: invoked by orchestrator during [researching] phase
- prompt-optimizer: invoked by evaluator when score < 7
- product-owner: invoked by evaluator for process improvements
- agent-architect: invoked by capability-analyst when gaps identified
- browser-automation: invoked by orchestrator for E2E testing
- visual-tester: invoked by orchestrator for visual regression

Mode 'all' should be used only for agents that can be both
primary (user-facing) and subagent (invoked by other agents).

.kilo/agents/agent-architect.md

@@ -1,6 +1,6 @@
 ---
 name: Agent Architect
-mode: all
+mode: subagent
 model: ollama-cloud/nemotron-3-super
 description: Creates, modifies, and reviews new agents, workflows, and skills based on capability gap analysis
 color: "#8B5CF6"

.kilo/agents/browser-automation.md

@@ -1,6 +1,6 @@
 ---
 description: Browser automation agent using Playwright MCP for E2E testing, form filling, navigation, and web interaction
-mode: all
+mode: subagent
 model: ollama-cloud/glm-5
 color: "#1E88E5"
 permission:

.kilo/agents/history-miner.md

@@ -1,6 +1,6 @@
 ---
 description: Analyzes git history to find duplicates and past solutions, preventing regression and duplicate work
-mode: all
+mode: subagent
 model: ollama-cloud/nemotron-3-super
 color: "#059669"
 permission:

.kilo/agents/product-owner.md

@@ -1,6 +1,6 @@
 ---
 description: Manages issue checklists, status labels, tracks progress and coordinates with human users
-mode: all
+mode: subagent
 model: ollama-cloud/glm-5
 color: "#EA580C"
 permission:

.kilo/agents/prompt-optimizer.md

@@ -1,6 +1,6 @@
 ---
 description: Improves agent system prompts based on performance failures. Meta-learner for prompt optimization
-mode: all
+mode: subagent
 model: qwen/qwen3.6-plus:free
 color: "#BE185D"
 permission:

.kilo/agents/system-analyst.md

@@ -1,6 +1,6 @@
 ---
 description: Designs technical specifications, data schemas, and API contracts before implementation
-mode: all
+mode: subagent
 model: qwen/qwen3.6-plus:free
 color: "#0891B2"
 permission:

.kilo/agents/visual-tester.md

@@ -1,6 +1,6 @@
 ---
 description: Visual regression testing agent that compares screenshots and detects UI differences using pixelmatch and image diff
-mode: all
+mode: subagent
 model: ollama-cloud/glm-5
 color: "#E91E63"
 permission: