chore: archive stale notes, delete to-issues/to-prd skills, clean install.sh

- docs/notes/archive/: move ai-ethics-security-principles.md and
  team-self-organisation-sprint-brief.md (superseded/out of scope)
- plugins/bin/skills/: delete to-issues and to-prd (stale mattpocock
  adoptions with no Gitea target; replacement tracked separately)
- scripts/install.sh: remove dead .agents/skills/ deployment block and
  provider skill adapter symlink code; neither path exists in this repo

Closes items 8, 9, 10 of issue #15.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/notes/archive/ai-ethics-security-principles.md

@@ -0,0 +1,89 @@
+# Exploration Note: Core Principles — AI Ethics & Security
+
+## Purpose
+
+Brief for a `/grill-with-docs` session. Goal: define the scope, structure, and tier placement of core principles governing AI ethics and security before writing any content.
+
+## What we want to build
+
+A set of guiding principles covering:
+
+- **Ethics** — responsible use of AI in development (trust, transparency, human oversight, bias, accountability)
+- **Security** — secure use of AI tooling (prompt injection, credential handling, supply chain, code review hygiene, data exposure)
+- **Other candidates** — privacy, auditability, scope creep (AI doing more than asked), agent autonomy limits
+
+These would live somewhere in this repo and be deployed to `~/.claude/` via `install.sh`.
+
+## Key question the grill must resolve
+
+**Tier placement** — the two-tier CLAUDE.md model (ADR-0005) means this decision has architectural weight:
+
+- **Tier 1 (always-on)** — universal rules in `providers/claude-code/CLAUDE.md`; loaded every session; must apply everywhere
+- **Tier 2 (on-demand)** — topic files in `core/instructions/<topic>.md`; agent reads when task context is relevant
+
+Getting this wrong either bloats every session's context (over-elevated rules) or silently drops rules that should always apply (under-elevated rules).
+
+## What the grill should challenge
+
+1. Which principles are truly universal (always-on) vs. task-specific (on-demand)?
+2. Should ethics and security be one file or separate files?
+3. Is "security" about agent behavior, or developer practice, or both? They have different owners.
+4. Does any of this duplicate what's already in the always-on section of CLAUDE.md (e.g. "require explicit confirmation for irreversible actions" is already there)?
+5. How do project-level overrides interact — can a project suppress a global ethics rule? Should it be able to?
+6. What's the enforcement model — these are instructions to an AI, not code. How do we verify they hold?
+
+## Context the next session needs
+
+- Read `CONTEXT.md` — domain language and existing principles
+- Read `docs/VISION.md` — long-term direction, especially the Management Application (these principles will eventually be configurable in the UI)
+- Read `providers/claude-code/CLAUDE.md` — the always-on section, to avoid duplicating what's already there
+- Read `docs/adr/0005-two-tier-claude-md.md` — rationale for the two-tier model
+- Chunk dev workflow: grill → `/to-prd` → `/to-issues` → `/tdd` → architecture review
+
+## Session flow
+
+### Step 1 — Research sub-agent (run first, before the grill)
+
+Spawn a general-purpose sub-agent to explore the space and return material for the grill to work with. Give it this brief:
+
+> Research AI ethics and AI security principles relevant to a software development context. Cover:
+>
+> - Established frameworks and standards (EU AI Act, NIST AI RMF, OWASP LLM Top 10, IEEE Ethically Aligned Design, Google/Microsoft/Anthropic responsible AI principles)
+> - What practicing dev teams actually use — concrete rules, not abstract values
+> - Security-specific: prompt injection, credential exposure, supply chain risks, code review hygiene, data leakage from context windows
+> - Ethics-specific: human oversight, transparency, bias in generated code, accountability, scope creep / agent autonomy limits
+> - Examples of how other orgs have written these as actionable developer guidelines (not mission statements)
+>
+> Do not just summarize — propose options. For each topic area, give 2–3 distinct approaches with a recommendation and the tradeoff. Flag anything creative or non-obvious. The output will feed a grill session where I'll iterate and refine.
+
+Let the agent return its full output before starting the grill.
+
+### Step 2 — Grill session (`/grill-with-docs`)
+
+Run the grill with both this note and the agent's research output as context. The grill covers two tracks:
+
+**Track A — Structure (what the grill always does)**
+Challenges tier placement, file structure, and terminology against CONTEXT.md and existing ADRs (see "Key questions" above).
+
+**Track B — Content ideation (added scope)**
+Uses the research output to iterate on the actual principles. The grill should:
+- Challenge each proposed principle — is it actionable or a platitude?
+- Force a choice when the agent offers options: pick one, name the tradeoff
+- Identify gaps the research missed
+- Stress-test principles against real scenarios ("a junior dev asks the agent to commit credentials — does this rule catch it?")
+
+The grill closes when both tracks are resolved: structure is decided and a draft principle set is agreed.
+
+---
+
+## Session start — paste this to begin tomorrow
+
+```
+I want to work on core principles for AI ethics and security in this repo. Start by reading docs/notes/ai-ethics-security-principles.md for full context.
+
+Then follow the two-step session flow in that note:
+1. Spawn a general-purpose research sub-agent with the brief from the note. Wait for it to finish.
+2. Run /grill-with-docs with both the note and the agent output as context.
+
+The grill has two tracks: structure (tier placement, file layout) and content ideation (actual principles). Both must be resolved before we close.
+```