refactor: refocus ArcheFlow as workspace orchestrator, not feature-dev competitor

- README: lead with af-sprint (parallel multi-project), af-review (post-impl quality)
- Sprint skill: L/XL code tasks use feature-dev style (explore→plan→impl→self-review)
  instead of PDCA. Reserve PDCA for writing/research domains.
- Session start: route to af-sprint/af-review/af-run based on task type
- Explicitly state: for single-feature dev, use feature-dev plugin instead

skills/sprint/SKILL.md

@@ -105,11 +105,44 @@ For each task in the batch, decide the execution strategy:
 | Signal | Strategy | What happens |
 |--------|----------|-------------|
 | Estimate S, clear scope | **Direct** | Spawn Agent() with task description, no orchestration |
-| Estimate M, multi-file | **Pipeline** | Spawn Agent() with af-run --strategy pipeline |
-| Estimate L/XL, complex | **PDCA** | Spawn Agent() with af-run --strategy pdca |
+| Estimate M, multi-file | **Direct+** | Spawn Agent() with task + "read code first, run tests after" |
+| Estimate L/XL, code | **Feature-dev style** | Agent explores → implements → self-reviews (see below) |
+| Estimate L/XL, writing | **PDCA** | Use af-run with writing domain archetypes |
 | Task contains "validate", "test", "lint", "check" | **Direct** | Cheap analytical task, no orchestration |
 | Task contains "review", "audit", "security" | **Review** | Spawn Guardian + relevant reviewers only |
 
+### L/XL Code Task Template (feature-dev style)
+
+For complex code tasks, give the agent a structured process instead of PDCA:
+
+```
+Agent(
+  description: "<project>: <task-short>",
+  prompt: "You are working on project <project> at <path>.
+    Task: <task description>
+
+    Follow this process:
+    1. EXPLORE: Read CLAUDE.md, docs/status.md, and the relevant source files.
+       Understand existing patterns before writing anything.
+    2. PLAN: Identify 2-3 files to change. Write a brief plan (what, where, why).
+       If ambiguous, list your assumptions.
+    3. IMPLEMENT: Make the changes. Follow existing code patterns strictly.
+    4. TEST: Run the project's test suite. Fix any failures.
+    5. SELF-REVIEW: Before committing, re-read your diff. Check:
+       - Error handling: what happens when this fails?
+       - Protocol compliance: am I using the right function signatures?
+       - Tests: did I test the important paths?
+    6. COMMIT + PUSH: Conventional commits, signed, pushed.
+
+    <standard rules>
+
+    STATUS: DONE | DONE_WITH_CONCERNS | NEEDS_CONTEXT | BLOCKED"
+)
+```
+
+This gives the agent feature-dev's structured exploration without the multi-agent overhead.
+For writing/research L/XL tasks, use af-run instead — archetypes add value where linters don't exist.
+
 **Agent spawn template:**
 
 For each task in the batch, spawn an Agent in the SAME message (parallel dispatch):

skills/using-archeflow/SKILL.md

@@ -17,16 +17,27 @@ Where `<domain>` is auto-detected: `writing` if `colette.yaml` exists, `research
 
 During runs, follow the `archeflow:presence` skill for output format: show outcomes not mechanics, one line per phase, value at the end.
 
-## IMPORTANT: When to Activate
+## IMPORTANT: When to Use What
 
-You MUST use ArcheFlow orchestration (load `archeflow:orchestration` skill and follow its steps) for any task that matches:
+### Use `/af-sprint` (primary mode) when:
+- User says "run the sprint", "work the queue", "go autonomous"
+- Multiple tasks are pending across projects
+- The workspace queue (docs/orchestra/queue.json) has pending items
 
-- **New features** -- any feature touching 2+ files
-- **Refactoring** -- structural changes across modules
-- **Security-sensitive changes** -- auth, encryption, input handling, API keys
-- **Bug fixes with unclear root cause** -- use Explorer to investigate first
-- **Code review requests** -- spawn Guardian + relevant reviewers
-- **Multi-file changes** -- anything beyond a single-file edit
+### Use `/af-review` when:
+- User wants to review code before merging
+- A diff, branch, or commit range needs quality check
+- Security-sensitive changes need Guardian analysis
+
+### Use `/af-run` (deep orchestration) when:
+- **Writing/research tasks** -- archetypes add value where linters don't exist
+- **Security-sensitive code changes** -- auth, encryption, API keys
+- **Complex multi-module refactors** with unclear approach
+
+### Do NOT use ArcheFlow for:
+- **Single-feature code development** -- use `feature-dev` plugin or work directly
+- **Simple fixes** -- just do them
+- **Questions, exploration, reading** -- no code changes needed
 
 Choose the workflow based on risk: