feat(P06): Integration & hardening — INTEG-01..05, MULTI-04

- INTEG-01: E2E ideation test (19 tests with proper structure)
- INTEG-02: E2E multi-project test (14 tests)
- INTEG-03: Version bump 0.9.0 → 0.10.0
- INTEG-04: AGENTS.md and README updates
- INTEG-05: All 594 tests passing
- MULTI-04: max_concurrent_projects config in ParallelizationConfig
- Fixed e2e-ideation test nesting and assertion issues

---ci---
phase: 6
milestone: v0.10
status: execute
decisions:
  - id: INTEG-01
    decision: E2E ideation test covers mechanical, acceptance, cascade, external, cross-project, chaos, spec
    rationale: 19 tests covering all ideation engine methods
    confidence: 0.95
  - id: INTEG-03
    decision: Version bumped to 0.10.0
    rationale: Minor update per semver for new ideation and multi-project features
    confidence: 0.99
  - id: MULTI-04
    decision: max_concurrent_projects added to ParallelizationConfig
    rationale: Controls parallel execution limit for multi-project pipelines
    confidence: 0.90
requirements:
  covered: [INTEG-01, INTEG-02, INTEG-03, INTEG-04, INTEG-05, MULTI-04]
---/ci---

README.md

@@ -63,6 +63,28 @@ ciagent quick "Add authentication middleware"
 # Check project status (reads from git log + branches)
 ciagent status
 
+# Discover improvement opportunities
+ciagent ideate                        # Mechanical tier (always available)
+ciagent ideate --category security    # Focus on specific categories
+ciagent ideate --affected             # Cascade impact analysis
+ciagent ideate --spec                 # Specification completeness analysis
+ciagent ideate --external             # npm audit + dependency staleness
+ciagent ideate --cross-project        # Cross-project pattern mining
+ciagent ideate --project all          # Run across all active projects
+ciagent ideate --output json          # JSON output mode
+ciagent ideate --output markdown      # Markdown output mode
+
+# Manage multiple projects
+ciagent projects list                 # List all registered projects
+ciagent projects add <slug> <name>    # Add a new project
+ciagent projects set <slug>           # Set the active project
+
+# Run with ideation stage
+ciagent run --ideate                  # Insert IDEATE stage between RESEARCH and PLAN
+
+# Run across all active projects
+ciagent run --project all             # Execute pipeline for each project
+
 # Review autonomous decisions (extracted from git log ---ci--- blocks)
 ciagent audit
 ciagent audit --verbose
@@ -77,7 +99,7 @@ ciagent rollback 1
 ciagent ship 1
 ```
 
-## Git-Native Architecture (v0.9.0)
+## Git-Native Architecture (v0.10.0)
 
 ### The Commit Schema
 
@@ -111,7 +133,7 @@ requirements:
 
 | Where | What | Why |
 |-------|------|-----|
-| `.ciagent/config.json` | Autonomy, thresholds, git strategy | Controls system behavior before any commits exist |
+| `.ciagent/config.json` | Autonomy, thresholds, git strategy, ideation, multi-project | Controls system behavior before any commits exist |
 | `.ciagent/PROJECT.md` | Vision, core value, requirements, constraints, key decisions table | Long-lived strategic reference |
 | `.ciagent/ARCHITECTURE.md` | System architecture, component boundaries, data flow | Long-lived technical reference |
 | `.ciagent/ROADMAP.md` | Phase breakdown, milestone mapping, success criteria | Long-lived planning reference |
@@ -204,7 +226,8 @@ CIAgent uses `.ciagent/config.json` for project configuration:
   "parallelization": {
     "enabled": true,
     "max_concurrent_agents": 5,
-    "min_plans_for_parallel": 2
+    "min_plans_for_parallel": 2,
+    "max_concurrent_projects": 3
   },
   "verification": {
     "automated_only": true,
@@ -221,6 +244,25 @@ CIAgent uses `.ciagent/config.json` for project configuration:
     "branching_strategy": "phase",
     "auto_commit": true,
     "auto_push": false
+  },
+  "ideation": {
+    "enabled": true,
+    "categories": ["security", "quality", "architecture", "coverage", "improvement"],
+    "confidence_threshold": 0.6,
+    "max_ideas": 20,
+    "external_signals": {
+      "npm_audit": true,
+      "osv_advisories": true,
+      "dependency_staleness": true
+    },
+    "cross_project": {
+      "enabled": false,
+      "similarity_weight": 0.5
+    },
+    "chaos": {
+      "enabled": true,
+      "scenarios": ["backend_unavailable", "requirement_change", "test_coverage_drop"]
+    }
   }
 }
 ```
@@ -230,9 +272,9 @@ CIAgent uses `.ciagent/config.json` for project configuration:
 ### Pipeline
 
 ```
-SPECIFY → CLARIFY → RESEARCH → PLAN → EXECUTE → TEST → VERIFY → COMPLETE
-                 ↕               ↕         ↕     ↕      ↕
-            (questions)    (auto-decide) (auto-run) (auto-test) (auto-verify)
+SPECIFY → CLARIFY → RESEARCH → IDEATE → PLAN → EXECUTE → TEST → VERIFY → COMPLETE
+                 ↕               ↕        ↕         ↕     ↕      ↕
+            (questions)    (auto-decide) (ideas) (auto-run) (auto-test) (auto-verify)
 ```
 
 ### Git-Native Core Modules
@@ -278,6 +320,55 @@ Decisions are committed to git as `decision` type commits. The audit trail is `g
 | solution-writer | Solution docs | Produces structured solution documents from plan + requirements |
 | phase-researcher | Phase research | Extracts decisions, lessons, risks from git log for a specific phase |
 
+### Ideation
+
+CIAgent includes a built-in ideation engine that discovers improvement opportunities from git-native signals:
+
+1. **Tier 1 — Mechanical**: Mines git history for uncovered requirements, repeated lessons, low-confidence decisions, escalation patterns, coverage gaps, architecture drift, and verification inversions
+2. **Tier 2 — Backend-enriched**: When a backend is available, prioritizes mechanical findings and suggests novel improvements
+3. **Tier 3 — Cross-project**: Mines patterns from other projects in the multi-project registry
+
+```
+ciagent ideate                          # All mechanical tiers
+ciagent ideate --category security      # Security-focused ideas
+ciagent ideate --affected               # Cascade impact from current changes
+ciagent ideate --spec                   # Specification completeness analysis
+ciagent ideate --external               # npm audit + OSV advisories
+ciagent ideate --cross-project           # Cross-project pattern mining
+ciagent ideate --project all             # Across all active projects
+ciagent ideate --output json             # Machine-readable output
+```
+
+### Multi-Project
+
+CIAgent supports multi-project workflows with `--project` flags:
+
+```bash
+# Initialize multiple projects
+ciagent projects add task-api "Task API"
+ciagent projects add auth-svc "Auth Service"
+
+# Run ideation across all projects
+ciagent ideate --project all
+
+# Run pipeline for a specific project
+ciagent run --project task-api
+
+# Run pipeline across all projects
+ciagent run --project all
+```
+
+Commit messages include project tracking in `---ci---` blocks:
+
+```
+---ci---
+phase: 5
+milestone: v0.10
+project: task-api
+status: execute
+---/ci---
+```
+
 ### Verification Layers
 
 1. **Structural**: File existence, import/export wiring, no stubs