chore: add Codex and agent workflow foundation

docs/MACHINE_SETUP.md

@@ -0,0 +1,37 @@
+# Machine Setup
+
+## Goal
+
+Bring a new machine to a usable Codex development state with minimal local-only setup.
+
+## Local-only prerequisites
+
+Not stored in the repo:
+- Codex authentication
+- personal shell setup
+- secrets/API keys
+- local editor preferences
+
+## Repository bootstrap
+
+1. Clone the repository
+2. Checkout `develop`
+3. Read:
+   - AGENTS.md
+   - docs/WORKFLOW.md
+   - docs/TASK_TEMPLATE.md
+4. Ensure Codex can see:
+   - AGENTS.md
+   - .codex/config.toml
+   - .codex/agents/*
+   - .agents/skills/*
+
+## Validation checklist
+
+A machine is considered ready when:
+- repo is cloned
+- correct branch is checked out
+- Codex authentication is working
+- AGENTS.md is present at repo root
+- .codex/config.toml is present
+- task branches can be created from develop

docs/TASK_TEMPLATE.md

@@ -0,0 +1,25 @@
+# Task Template
+
+Use this structure for Codex implementation tasks.
+
+## Required opening
+
+- confirm branch strategy
+- name the branch to use
+- state whether remote update succeeded or local state is being used
+
+## Required execution structure
+
+1. files to change
+2. short design explanation
+3. code/doc/test changes
+4. commit message
+5. merge target
+6. stop
+
+## Constraints
+
+- no work on main
+- no work on develop
+- no history rewrite
+- no broadening scope without approval

docs/WORKFLOW.md

@@ -0,0 +1,33 @@
+# Workflow
+
+## Branch policy
+
+Protected branches:
+- main
+- develop
+
+Normal task flow:
+1. checkout develop
+2. create feature/<task-name>
+3. implement the task
+4. commit changes
+5. merge feature branch into develop
+6. delete feature branch when appropriate
+
+## When to use an umbrella branch
+
+Use an umbrella branch only for a large coordinated effort that spans multiple dependent feature branches.
+
+If used, document:
+- why it exists
+- its exact name
+- which child branches merge into it
+- when it is expected to merge back into develop
+
+## Task discipline
+
+Each task should:
+- have one clear goal
+- have one task branch
+- end with a commit and merge target confirmation
+- not silently include unrelated cleanup