docs: add phased implementation plan and architecture decision records

Turns the design doc into an ordered, dependency-correct build plan (phases
0-9) with an exit criterion per phase, and records the twelve architectural
decisions it rests on as ADRs.

Decisions: single Rust binary with routed compose services; Streamable HTTP
only; per-agent bearer tokens with clientInfo as a display hint only; SQLite;
get_rules delivered via session gating; full-document rule delivery; project_id
from day one; enforcement tier scoped to Bridle-mediated actions; stable tool
list on upstream failure; OpenAI-compatible embeddings with model/dim guarding;
pattern RAG gated behind a spike; CLAUDE.md + AGENTS.md as v1 renderer targets.

Deviates from the design doc's original 1-8 ordering by moving the audit log
and multi-project schema into phase 1, building the admin API incrementally
rather than all at the Web Panel phase, downgrading vendor guardrail sourcing
to manual-first, and gating the pattern-example RAG behind a validation spike.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019RZerbsHGF9Ka3bKhCjJ9m

docs/adr/0012-v1-renderer-targets.md

@@ -0,0 +1,28 @@
+# ADR-0012: `CLAUDE.md` and `AGENTS.md` as the v1 renderer targets
+
+**Status:** Accepted (2026-08-08)
+
+## Context
+
+The design doc names four agent targets: Claude, Codex, Kimi, and DeepSeek. Phase 2 exists to prove
+the single-source-of-truth thesis — that one canonical document renders correctly into genuinely
+different agent formats. Shipping only one renderer would not prove it, because nothing would force
+the canonical schema to stay format-neutral; it would quietly shape itself around the single target.
+Shipping all four means four renderers and four golden-test suites before the thesis is validated
+even once.
+
+## Decision
+
+Ship **`CLAUDE.md` (Claude conventions) and `AGENTS.md` (Codex)** at 1.0. Kimi and DeepSeek land
+post-1.0 as `AGENTS.md` dialects carrying the more explicit, step-by-step phrasing the design doc
+calls for on weaker instruction-followers.
+
+## Consequences
+
+- Two formats different enough to keep the canonical schema honestly format-neutral.
+- Golden-file tests cover both from phase 2; renderer correctness is that phase's actual
+  deliverable.
+- The renderer must be structured so a dialect (same base format, different phrasing verbosity) is
+  a cheap addition rather than a fork.
+- `agent_profiles` entries for Kimi and DeepSeek may exist in the canonical schema before their
+  renderers do.