Phase 1-3: Add memory, skills, and improvement systems

- memory/: cross-session project memory with decisions, lessons, failures,
  architecture, and sessions categories. Each has format templates and
  lifecycle documentation.
- skills/: 12 reusable specialized methodologies (tdd, systematic-debugging,
  architecture-design, code-review, security-review, repository-analysis,
  failure-analysis, refactoring, test-analysis, incident-investigation,
  browser-automation, research). Each has frontmatter and methodology sections.
- improvements/: proposal-based improvement system requiring human approval.
- scripts/memory-lifecycle.sh: deterministic memory operations (recall, store,
  list, search, sessions, cleanup).
- scripts/test-memory-system.sh: 12 structural tests for all new systems.
- orchestrator.md: added Memory Recall stage, Learning and Memory Storage
  stage, Improvement Proposals workflow, memory/skills rules, and 3 new
  actions (A23-A27) to the action catalog. Updated behavioral acceptance test
  and state separation model.
- All 12 subagents: added Memory & Skills Awareness sections with recall
  and store instructions.
- docs/AGENT_ARCHITECTURE.md: documented memory, skills, and improvements
  systems (sections 12-14). Updated action count (27), state model, and
  remaining weaknesses.
- README.md: documented new systems, updated repository layout, added
  test-memory-system.sh documentation.

All 39 tests pass (16 architecture + 12 memory + 11 bootstrap).

skills/research/SKILL.md

@@ -0,0 +1,57 @@
+---
+name: research
+description: Research methodology — structured investigation to answer questions
+version: "1.0"
+owner: Explorer + Writer
+prerequisites: question defined
+---
+
+# Research
+
+## When to use this skill
+
+- A question needs a well-researched answer
+- Comparing alternatives
+- Understanding best practices
+
+## Step-by-step procedure
+
+### 1. Define the question
+- What exactly are we trying to find out?
+- What constitutes a good answer?
+- What are the constraints?
+
+### 2. Gather sources
+- Internal: code, docs, memory, agent reports
+- External: web, documentation sites, official references
+- Evaluate source reliability
+
+### 3. Analyze
+- Compare findings across sources
+- Identify contradictions
+- Assess confidence in each finding
+
+### 4. Synthesize
+- Combine findings into a coherent answer
+- Distinguish facts from opinions
+- State what remains uncertain
+
+### 5. Record
+- Document findings with sources
+- Update memory if findings are durable
+- Share with relevant agents
+
+## Common pitfalls
+
+- Accepting the first source without cross-referencing
+- Confusing opinions with facts
+- Not citing sources
+- Going too deep (research rabbit holes)
+- Not stopping when the question is answered
+
+## Exit criteria
+
+- Question answered with evidence
+- Sources cited
+- Confidence level stated
+- Uncertainties documented